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Background: The advance of next generation sequencing (NGS) leads to give the abundant genetic information of breast cancer (BC). We developed the prediction model of neoadjuvant chemotherapy (NAC) response and long term survival using genetic characteristics in cooperation with clinicpathologic features. Methods: Early and locally advanced BCs which would be planned to receive standard NAC (four cycles of anthracycline plus cyclophosphamide and four cycles of docetaxel or docetaxel plus trastuzumab for human epidermal growth factor receptor 2[HER2+] disease) followed by curative surgery. We prospectively collected tumor tissue and matched blood three times for each patients: at BC diagnosis (T1), three weeks after the first cycle of NAC (T2), and curative surgery (T3). Whole exome sequencing (WES) and RNASeq were performed to detect somatic mutation, mutational signature, tumor mutational burden (TMB) and PAM50 prediction was to classify intrinsic subtype. In terms of clinical variables, clinical stage and IHC subtype at diagnosis, pathologic complete response (pCR), residual cancer burden (RCB) class and distant recurrence free survival (DRFS) were used for prediction model development. Logistic regression was used for predicting RCB class and pCR with clinical and genomic variables at T1. Univariate and multivariate Cox regression were performed to identify prognostic factors for DRFS. Results: In total, 210 patients who were treated with scheduled NAC were enrolled. Finally, WES in 252 BC tissues (T1:123, T2:106 and T3:23) RNASeq in 198 BC tissues (T1:100, T2:77 and T3:21) were conducted from 123 patients. In NAC response, 52 patients achieved pCR(42.3%) and 14 patients were in RCB class 3, 39 in class 2, 14 in class 1 and 51 in class 0. Median follow up duration was 44months and distant recurrence was observed in 13 patients. TP53 mutation (60%) was the most commonly detected genetic alteration followed by TTN(31%), ERBB2(25%) and PIK3CA(18%). Eight BCL11A (3%) and 3 MPL mutations (1%) were also observed respectively. Serial tumor sequencing suggested that mutation profile have not changed during NAC. In terms of mutational signature, signature 3 was most frequently observed and no difference was observed in serial sequencing data. In addition, APOBEC (sig.2) and HRD (sig.3) were observed differently according to intrinsic subtype. In terms of intrinsic subtype, basal subtype decreased during NAC and luminal A type increased. Median TMB was 87 (range, 14-570). In prediction model, clinical N3(cN3) stage (Odds ratio [OR] of cN3 vs. not : 4.536, 95% confidence interval [CI]: 0.925, 44.016, p=0.042) and intrinsic subtype at BC diagnosis (OR of non-luminal vs. luminal types: 0.208, 95% CI: 0.062, 0.604, p=0.001) were associated with pCR. Clinical stage (OR of clinical stage III vs. II: 4.115, 95% CI: 1.094, 19.217, p=0.021), TMB (OR of TMB high vs. low: 0.255, 95% CI: 0.043,1.042, p.value=0.045), MPL genetic alteration (OR of mutation vs. wild type: 16.347, 95% CI: 0.797,1013.88, p.value=0.037), BCL11A (OR of mutation vs. wild type: 16.347, 95% CI: 0.797,1013.88, p.value=0.037) were associated with RCB class (3 vs. others). In terms of DRFS, prediction model consisted of clinical stage (Hazard ratio [HR] of stage III vs. II: 3.496, 95% confidence interval [CI]:1.337, 5.654), PIK3CA (HR of mutation vs. wild type: 1.572, 95% CI:-0.008, 3.152) TMB (HR of high vs. low: -1.999. 95% CI:-3.669, -0.329) had c-index of 0.861(95% CI:0.805, 0.916). Conclusions: During NAC, somatic mutation and mutation signature were consistently maintained while intrinsic subtype dynamically changed. In prediction model, TMB, PIK3CA mutation and clinical stage showed predictive roles on DRFS of BC in NAC setting. Citation Format: Ji-Yeon Kim, Kyunghee Park, Woong-Yang Park, Jeong Eon Lee, Seok Won Kim, Seok Jin Nam, Se Kyung Lee, Zhengyan Kan, Yeon Hee Park. Prediction model of the response of neoadjuvant chemotherapy and long term survival according to multi-omic profiling in cooperation with clinicopathologic features in patients with breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-08-07.

Background. Sentinel lymph node biopsy (SLNB) is currently the standard axillary staging procedure for clinically node-negative breast cancer. According to the ACOSOG Z0011 trial, axillary lymph node dissection (ALND) is now often omitted for clinically node-negative cT1-2 breast cancer patients undergoing breast-conserving surgery even if 1 or 2 metastatic lymph nodes (LN) are identified. It was shown that radiotherapy contributes to regional control of the axilla non-inferior to ALND even in the presence of metastatic LNs. Furthermore, LN metastasis has a limited role in planning adjuvant systemic therapy for hormone receptor-negative breast cancers, and also for hormone receptor-positive, HER2-negative breast cancer with increased use of genomic assays. SLNB is not without complications and omitting axillary staging operation could improve quality of life. Trial Design. In this multicenter, phase III randomized controlled trial including 9 study sites in South Korea, we plan to 1:1 randomize 1734 patients to either omit SLNB (Arm 1) or receive SLNB (Arm 2). Additional ALND can be performed according to the discretion of the surgeon according to the SLNB results. All patients must receive whole-breast irradiation ± tumor bed boost. The recommended upper margin of the radiation field is within 2cm of the humeral head. ClinicalTrials.gov identifier: NCT04303715. Eligibility. Inclusion criteria: women ≥19 years; cT1-2N0M0 unilateral invasive breast carcinoma; all molecular subtypes; clinically and radiologically tumor size ≤ 5cm; clinically- and ultrasonogram-negative axillary lymph nodes, or no tumor on core needle biopsy or fine needle aspiration cytology in case of suspicious lymph nodes; candidate for breast-conserving surgery with no restriction to radiotherapy and adequate systemic therapy. Exclusion criteria: history of any malignancy within 5 years (exception: thyroid cancer and well-treated skin cancer except melanoma); bilateral breast cancer; neoadjuvant chemotherapy; candidate for total mastectomy; male breast cancer. Specific Aims. Primary objective is to test the hypothesis that omitting SLNB for breast cancer is non-inferior to axillary staging operation in terms of 5-year disease-free survival. Secondary objectives are to compare overall survival, distant metastasis-free survival, locoregional recurrence, quality of life assessment, and DFS and axillary recurrence according to molecular subtypes. Statistical Methods. With an expected 5-year DFS of 86% for Arm 2, Arm 1(SLNB omission) will be assessed with a non-inferiority limit of 5% and hazard ratio of 1.4, power 80%, and significance level of 5%, where 224 events are required. The calculated sample size is 780 per study arm, resulting in a total of 1,734 patients assuming a 10% drop-out rate. Present Accrual and Target Accrual. The first patient was randomized on September 15, 2020. As of July 9, 2021, 480 patients have been randomized. Target accrual of 1734 patients is expected to be complete by April 2023, with the primary endpoint analysis expected in 2028. Citation Format: Han-Byoel Lee, Ji Gwang Jung, Jung Min Chang, Ji Hyun Chang, Woo Kyung Moon, Kyung Hwan Shin, Il Yong Chung, Seok Jin Nam, Eun-Kyu Kim, Seeyoun Lee, Seho Park, Woo Sung Lim, Yongsik Jung, Wonshik Han. The NAUTILUS trial (No Axillary sUrgical Treatment In clinically Lymph node negative patients after UltraSonography): A prospective multicenter randomized phase III trial (NCT04303715) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr OT1-04-02.

Background: Neutrotrophin receptor tyrosine kinase (NTRK) gene fusions (NTRK1, NTRK2, or NTRK3) are oncogenic drivers of various tumor types. The NTRK fusion was detected in less than 5% of breast, colorectal, lung or any other types of cancers. However, large scaled next generation sequencing data for NTRK fusion in breast cancer have not existed. In this study, we performed RNASeq and fusion analysis including NTRK genes. Methods: We prospectively collected BC tumor tissues from the translational research conducted in Samsung Medical Center. Fusion was predicted from RNAseq using the following seven softwares(SWs): ChimeraScan, DeFuse, MapSplice, TophatFusion, STAR.Arriba, STAR.fusion, and STAR.SEQR. To remove false-positive fusion calls, calls less than 3 left/right spanning reads and 10 total supporting reads were removed. After filtering out the blacklist fusion calls which were recurrently detected, calls commonly predicted in more than two SWs were analyzed. Results: In total 629 BC samples, 613 samples were finally analyzed after quality control (QC) of RNASeq. According to immunohistochemistry (IHC) profile, 356(58.7%) was hormone receptor (HR) positive human epidermal growth factor receptor 2 (HER2) negative BC, 42 (6.9%) of HR positive HER2 positive BC, 53 (8.7%) of HR negative, HER2 positive and 155(25.6%) of triple negative BC (TNBC). PAM50 prediction informed that 174(28.9%) of luminal A, 151(24.6%) of luminal B, 170 (27.7%) of basal-like, 85 (13.9%) of HER2-enriched and 33 (5.4%) of normal. In median number of fusion events, 12 was called by ChimeraScan (Interquartile range [IQR]: 5, 33), 57 by DeFuse (IQR: 33, 82), eight by Mapsplice (IQR: 5, 12), two by TophatFusion (IQR: 0, 4), five by STAR.Arriba (IQR: 2, 12), two by STAR.fusion (IQR:0, 5) and three by STAR.SEQR fusion caller (IQR: 1, 7) after call filtering. After initial fusion call, we excluded the results from ChimeraScan and DeFuse fusion callers because of discrepancy of number of called fusion events. In five fusion callers, median number of fusion events was eight (IQR :2,20) per BC sample. In terms of NTRK fusion, we detected NTRK2-BANCR fusion event in one TNBC patients (1/425, 0.2%). This fusion was detected in four of five SWs for fusion detection with significant number of supporting reads in RNASeq. NTRK2-BANCR fusion was the out-of-frame fusion, which C-terminal truncated protein kinase domain of NTRK2 and its partner long non-coding RNA BANCR was combined and RNA expression of this fusion was increased. Other fusion events of BCs were NCOR2-PARP4 (3.7%), BRD4-NWD1 (3.7%), ESR1-RGS17 (1.8%), FGFR1-TACC1 (0.2%) and MKRN1-BRAF (0.2%). In BC subtype according to IHC, fusion events were more frequently observed in TNBC compared with other subtypes regardless of the type of fusion filters. In terms of intrinsic subtype, fusion events were most frequently observed in basal like type and least in normal like intrinsic subtype (all ps Citation Format: Ji-Yeon Kim, Kyunghee Park, Woong-Yang Park, Jeong Eon Lee, Seok Won Kim, Seok Jin Nam, Jonghan Yu, Young-Hyuck Im, Jin Seok Ahn, Yeon Hee Park. Fusion analysis including NTRK fusion in breast cancers (BC): From RNASeq data analysis from 629 BC tissue samples [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-13-08.

Introduction Adding pertuzumab(P) on trastuzumab(H) with cytotoxic chemotherapy increased pathologic complete response (pCR) of early or locally advanced HER2 positive breast cancer (EBC) with neoadjuvant chemotherapy. Since 63.6% of pCR rate has been reported from TRYPHAENA trial, TCHP regimen has been used as a standard of neoadjuvant treatment regimen for patients with HER2 positive EBC. However, this regimen has profound toxicities in terms of myelosuppression, neurotoxicity, and etc. Furthermore we still need more information on clinical outcomes and toxicities with this regimen. Therefore, we report real world experience of EBC patients treated with neoadjuvant TCHP followed by curative surgery. Methods We retrospectively reviewed electronic medical record of EBC patients who received neoadjuvant TCHP. Information which we gathered included patients’ and tumor characteristics at the time of diagnosis, details of neoadjuvant chemotherapy, pathologic assessment of tumor response to neoadjuvant TCHP and recurrence free survival after curative surgery. pCR was defined as absence of residual invasive cancer on pathologic evaluation of the resected breast specimen and all sampled regional lymph nodes (ypT0/isN0). Results Between February 2016 and August 2019, 447 patients were treated with neoadjuvant TCHP followed by curative surgery. Median age at BC diagnosis was 56. In clinical stage, stage II was 54.6% and 45.4% of stage III and hormone receptor (HR) positive BC was 48.3%. Most commonly reported adverse event(AE) was mucositis (84%) followed by diarrhea (77%). In terms of Grade 3 AE, anorexia(6%), diarrhea(2%) were frequently observed and 9(2%) of febrile neutropenia occurred despite of prophylactic use of peg-filgrastim. Forty percent of patients experienced dose reduction due to AEs. Of 447 patients, 29% of patients underwent total mastectomy and 71% of breast conserving surgery. In terms of clinical outcome, pCR rate was 64%; 77% of HR negative BCs and 50% of HR positive BCs. Among baseline characteristics, high nuclear grade, high histologic grade, HR stats affected to pCR status (Ps Key words: neoadjuvant chemotherapy, HER2+ breast cancer, pertuzumab, pathologic complete response Citation Format: Ji-Yeon Kim, Seok Jin Nam, Seok Won Kim, Jonghan Yu, Byung Joo Chae, Se Kyung Lee, Jai Min Ryu, Jin Seok Ahn, Young-Hyuck Im, Yeon Hee Park. Real Would Evidence (RWE) of neoadjuvant docetaxel/carboplatin/trastuzumab/pertuzumab (TCHP) in patients with HER2 positive early or locally advanced breast cancer treated Single institutional experience [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS10-38.

Introduction: Patients with Hormone receptor (HR)-positive / HER2-negtive breast cancer have not received targeted therapy for Her2 based on criteria of the protein expression or DNA copy number amplification. However, the clinical meaning of the level of Her2 signaling activity has not been fully elucidated yet. We recently developed a novel technique of single-molecule protein-protein interaction (PPI) profiling to investigate the importance of HER2 signaling activity in this major subgroup of breast cancer. Methods: This study is a study with the biospecimen and registered medical record from the prospective collected cohort of Samsung Medical Center, and all of these biospecimens were provided by Samsung Medical Center BioBank. First, We selected 138 of 8463 patients who were diagnosed with invasive breast cancer by curative surgery between January 2008 and December 2013. Specimens were selected based on modified Allred Immunohistochemistry (IHC) scores; 6 for hormone receptors (ER/PR+) and 1 for Her2. Then, we applied the single-molecule co-immunoprecipitation, a novel technology determining protein-protein interactions (PPIs), to each selected biospecimen. PPI and expression level for HER2 protein of each tumor extract were analyzed with HER2-PPI-Dx kit. All the measurement were performed using a single-molecule fluorescence imaging equipment. Based on HER2 PPI and expression level analysis, we developed an algorithm based on the 72 patients’ samples which can predict the prognosis of these patients. This algorithm was validated with the samples from the other 66 patients. Results: In total, 138 samples from each patients (72 in training set and 66 in validation set) were analyzed. The median follow-up time was 68.0 (range: 7-123) months. Single-molecule measurement for HER2 level showed that clinical specimens showed significant differences in HER2-PPI level even though they had the same IHC score (65-fold from 117 patients with ‘HER2 IHC score: 0’ and 33-fold from 21 patients with ‘HER2-IHC score: 1’, respectively). For the training set, by combining HER2 PPI and HER2 protein expression data, we could select 12 patients (17%) as a high level HER2-PPI group. This high level HER2-PPI group showed the significantly poorer disease free survival (DFS) rate compared to that of the low level group (42% for high-level vs. 83% for low-level, p=0.001). For the validation set with the same cutoff, 17 patients (26%) with identified as high level HER2-PPI group. We still found a significantly poorer DFS rate in this group compared to that of the low level group (82% vs. 88%, p=0.033). For total 138 patients set, we found a significantly poorer DFS rate in this group compared to that of the low level group (p=0.014). Conclusion: Our results showed that HER2 PPI may have an important clinical meaning to identify a high risk of recurrence in the patients with strong HR-positive and HER2-negative breast cancers defined by conventional method. For those patients with high level HER2-PPI, HER2-targeted therapies may be beneficial despite of their HER2-negativity. This will be proved for the future. Citation Format: Hee Jun Choi, Hong Won Lee, Sangmin Kim, Tae-Young Yoon, Hyunwoo Kim, Seul Lee, Seok Jin Nam, Seok Won Kim, Sooyoun Cho, Yeon Hee Park, Jeong Eon Lee. Protein-protein interaction of HER2 predicts the prognosis of hormone receptor-positive HER2-negative breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-10-26.

Background: Estrogen receptor (ER) expression is a predictive and prognostic factor in breast cancer. While the clinical benefit of endocrine therapy is indisputable, evidence suggests patients with low-ER expression (immunohistochemistry (IHC) 1-10%) may be less likely to respond to endocrine therapy and have a prognosis similar to those with hormone receptor negative breast cancer, particularly in the setting of human epidermal growth factor receptor 2 (HER2) negative disease. The objective of this analysis was to estimate the proportion of low-ER expression among female breast cancer patients, and the clinicopathological characteristics, treatment patterns and clinical outcomes using real world data. Methods: A retrospective analysis was conducted using data from female breast cancer patients that underwent surgery with curative intent for invasive ductal or lobular breast cancer at Samsung Medical Center (Seoul, Korea) between January 2003 and December 2012. IHC was previously performed using standard procedures for determining ER, progesterone receptor (PR) and HER2 levels. PR expression was only used in determining triple-negative breast cancer (TNBC) status. ER-positive patients were further classified as ER expression low (1-10%) and high (>10%) using their Allred Proportion Score (score=2) and Intensity Score (score of 1, 2 or 3). Disease-free survival (DFS) was analyzed using Kaplan-Meier method. Results: The analysis included 5,930 patients with a median follow-up of 81 months. Overall, approximately 47% were stage 1, 41% stage 2, and 12% stage 3. Seventy-three percent of patients were ER+/HER2-, 13% TNBC, 8% ER+/HER2+ and 6% ER-/HER2+. The proportion of the cohort with low-ER expression was 2.0% (n=117); 63 (53.8%) and 54 (46.2%) with HER2- and HER2+ status, respectively. Among all ER+ women, 2.4% were classified as low-ER. The proportion of women with Ki-67 of ≥14 was greater in the low-ER/HER2- (90.0%) than the high-ER/HER2- cohort (43.3%) and similar to the TNBC cohort (92.2%). Low-ER/HER2- women were more likely to receive adjuvant chemotherapy (93.7%) than those with high-ER/HER2- (58%), which was comparable to women with TNBC (92.2%). Among those with HER2- status, low-ER patients were slightly less likely than their high-ER counterparts to have received adjuvant hormone therapy (92.1% vs 98.9%). Five-year DFS for the overall cohort was 91.7%; highest in the high-ER/HER2- cohort (94.0%), lowest in the TNBC cohort (81.3%) and 85.7% among low-ER/HER2- women. Conclusion: Women with low-ER/HER2- breast cancer had similar clinicopathological characteristics, treatment patterns, and prognosis compared with those with TNBC. Clinical implication of this low-ER subgroup needs to be elucidated in terms of intrinsic subtyping based on biology to enable optimal treatment. Further research is needed to understand predictive and prognostic factors associated with low-ER/HER2- disease. Citation Format: Yeon Hee Park, Vassiliki Karantza, Shawna R. Calhoun, Seri Park, Sohee Lee, Ji-Yeon Kim, Jong Han Yu, Seok Won Kim, Jeong Eon Lee, Seok Jin Nam, Gursel Aktan, Mark Marsico. Low estrogen receptor positive (1-10%) breast cancer prevalence, treatment patterns and prognosis: A single institution’s experience in Korea [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-09-05.

Background: Most of breast cancer patients survive for a long-term period. The existing assessment of survivors’ prognosis has had some limitations in breast cancer because it is based on an evaluation at the time of diagnosis. Conditional survival reflects change over time after diagnosis and treatment of cancer. Conditional disease-free survival (CDFS) and conditional overall survival (COS) can provide more accurate prognosis to breast cancer patients. In this study, we aimed to determine 5-years CDFS and COS according to disease-free period after diagnosis and treatment of breast cancer in Korea. Method: We retrospectively reviewed clinical data of 5664 patients aged 16 to 86 who underwent curative surgery for breast cancer between January 2000 and December 2008 at Samsung Medical Center, a single tertiary hospital in Korea. The CDFS and COS rates were based on cumulative DFS and OS estimates up to 15 years using the Kaplan-Meier method. Results: At baseline, each 5-years DFS and OS were 88.0% and 93.8%. For patients who kept disease free status from 1 to 9 years after surgery, the 5-years CDFS rates were calculated as 88.7%, 90.7%, 91.6%, 91.1%, 91.5%, 91.0%, 89.5%, 86.1% and 86.1%, respectively. The 5-year COS rates of the patients who had survived from 1 to 9 years after surgical treatment were calculated as 92.6%, 92.1%, 91.2%, 91.0%, 89.4%, 85.6%, 80.7%, 75.3%, and 73.0%, respectively. Conclusion: Our study showed that 5-years CDFS and COS for most patients who have breast cancer in Korea seemed to be good prognosis for a long time. However, cancer recurrence tended to occur after a long period postoperatively. Further study is required to identify risk factors associated with recurrence after several years in Korean breast cancer patients. Citation Format: Jee Hyun Ahn, Seok Jin Nam, Seok Won Kim, Jeong Eon Lee, Byung-Joo Chae, Se Kyung Lee, Jai Min Ryu, Jonghan Yu. The 5-years conditional disease free survival and overal survival for breast cancer patients in Korea [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-08-25.

Introduction: Neoadjuvant chemotherapy (NAC) enables curative surgery and deprives micrometastasis in locally advanced breast cancer (LABC). Indeed, response of NAC, representatives of pathologic complete response (pCR) as well as residual cancer burden (RCB) class, is the most powerful indicator to predict BC prognosis. Therefore, NAC has been commonly used to treat LABC especially for HER2+ and TNBC subtype. While BC was treated with NAC, BC pathologic characteristics could be switched as a consequence of NAC. However, serial tumor biopsies are not feasible in clinical practiceeven though NAC has been used “in vitro vehicle” for translational research. Therefore, plasma biomarker is unmet need for treatment response prediction. In this study, we aimed to identify potential plasma biomarkers using multiplex immunoassay in BC patients with NAC. In total, we evaluated 45 plasma biomarkers and analyzed the association between the level of biomarkers and clinical outcomes. Methods: This study was prospectively conducted for LABC patients with NAC. Patients were treated with a standard NAC protocol for 6 months, consisting of four cycles of adriamycin/cyclophosphamide (AC) (60/600 mg/m2) combination chemotherapies followed by four cycles of docetaxel(D) (80mg/ m2) chemotherapy. HER2+ BC patients were treated with docetaxel plus trastuzumab (DH) combination therapies after AC. Surgical response was evaluated according to pathologic complete remission (pCR) defined as no residual invasive carcinoma in primary tumor bed and axillary lymph node. We also calculated residual cancer burden (RCB) score based on surgical pathology report. For each patient, blood sampling were prospectively taken 3times; before treatment (T1), three weeks after the first cycle of AC (T2) and at surgery following six months of treatment (T3). Plasma samples were assayed by multiplex immunoassays for 45 biomarkers, including growth factor, cytokines and chemokines using 45-Plex Human ProcartaPlexTM Panel (Thermo Fisher Scientific, Inc. Carlsbad, CA, USA). Results: In total, 167 patients diagnosed with LABC were participated in serial plasma sampling. Fifty eight patients were diagnosed with HER2+ BCs (34.7%) and 63 of TNBCs (37.7%). Clinical stage at BC diagnosis was variate; 59 of stage II (35.3%), 108 of stage III (64.7%). After BC surgery, pCR (RCB class 0) was observed in 53 BCs (6 hormone receptor positive and HER2- BCs (13.0%), 27 HER2+ BCs (46.6%) and 20 TNBCs (31.7%)). In terms of RCB class, 20 BCs were class I, 63 of class II and 28 of class III. Two patients diagnosed with LABC had undergone disease progression during NAC. Among clinical variables, RCB class after NAC in LABC patients has the highest predictive value for relapse free survival (RFS) (c-index: 0.787, 95% confidence interval [CI]:0.690, 0.884, p-value Conclusion: Seven plasma protein expressions predict RCB class in LABC patients with NAC and predicted RCB class also has a similar predictive value for RFS compared with RCB class based on the result of curative surgery. Citation Format: Ji-Yeon Kim, Kyunghee Park, Hae Hyun Jung, Se Kyung Lee, Jonghan Yu, Jeong Eon Lee, Seok Won Kim, Seok Jin Nam, Yeon Hee Park. Serum protein expression predicts neoadjuvant chemotherapy response in patients with locally advanced breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-10-18.

Introduction Recent transcriptome analysis developed a holistic tumor microenvironment (TME) classification platform based on immune and fibrotic markers. This TME classification had four categories, immune enriched, fibrotic (IE/F); immune enriched, non-fibrotic (IE); Fibrotic (F); and Immune Desert (D). And these four TME subtypes are a predictive biomarker to immunotherapy in multiple cancer and four subtypes have been changed during treatment. Previously our study suggested baseline immune features and dynamic immune response on-treatment were predictive of treatment outcome in BC with neoadjuvant chemotherapy (NAC). In this study, we evaluated the impact of TME classification and dynamic change of TME classification on treatment outcome in BC with NAC. Methods Early and locally advanced BCs which would be planned to receive standard NAC (four cycles of anthracycline plus cyclophosphamide and four cycles of docetaxel or docetaxel plus trastuzumab for human epidermal growth factor receptor 2[HER2+] disease or six cycles of docetaxel, carboplatin, trastuzumab and pertuzumab for HER2+ disease) followed by curative surgery. We prospectively collected tumor tissue and matched blood three times for each patients: at BC diagnosis (T1), three weeks after the first cycle of NAC (T2), and curative surgery (T3). RNASeq was performed to classify TME subtype. In terms of clinical variables, clinical stage and IHC subtype at diagnosis, pathologic complete response (pCR), distant recurrence free survival (DRFS) and overall survival (OS) were used. Generalized logistic regression was used for predicting RCB class and pCR with clinical and genomic characteristics at T1. Kaplan-Meier analysis were performed to analysis DRFS and OS. Results In total, 210 patients who were treated with scheduled NAC were enrolled. Finally, RNASeq in 240 BC tissues (T1:119, T2:91 and T3:30) were conducted from 142 patients. In 119 BCs which was performed RNASeq at T1, hormone receptor(HR)+, HER2- BC was 32 (26.9%), 29 of HR+HER2+ BC (24.4%), 18 of HR-HER2+ BC (15.1%) and 44 of triple negative BC (TNBC) (37.0%). In TME classification, immune desert (D) was most frequently observed (45.3%), followed by IE (35.3%), F (10.1%) and IE/F (9.2%). The association between BC subtype and TME subtype suggested that HR+HER2- BC was frequently categorized into D (22 of 32, 68.8%) whereas TNBC was into IE (24 of 44, 54.5%) (p< 0.001). TME subtype has been dynamically changed during NAC. At T2, IE subtype was most frequently observed (27.5%) followed by D (25.3%), IE/F (24.2%) and F (23.1%). The inclination of TME change were different according to NAC response. In BC achieved pCR, IE/F subtype had increased (4 at T1 and 10 at T2) and decrease of D subtype (15 at T1 and 3 at T2). In BC with non-pCR, IE/F subtype had slightly increased at T2 (7 at T1 and 12 at T2) but there was no IE/F subtype at T3 point. Contrarily, D subtype had decreased at T2 but increased at T3 (39 at T1, 20 at T2 and 24 at T3). The impact of TME subtype was different according to pCR status. In BC with pCR, F subtype had poor prognosis in DRFS and OS compared to other subtype ([5year DRFS rate for F vs. others: 66.7% vs. 93.2%, p=0.028], [5year OS rate for F vs. others: 70.7% vs. 100%, p< 0.001]). In BC without pCR, there was no different DRFS and OS according to TME subtypes. Conclusion Our data suggested that TME subtype has been changed during NAC and the subtype switching was affected by the NAC response. Moreover, TME subtype may have prognostic role in DRFS and OS according to pCR status. Citation Format: ji-Yeon Kim, Kyunghee Park, woong-Yang Park, Jeong Eon Lee, Seok Won Kim, Seok Jin Nam, Se Kyung Lee, Yeon Hee Park. Tumor microenvironment subtype influence the response of neoadjuvant chemotherapy in breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-01-37.

Background Triple-negative breast cancer (TNBC) is known to have a higher risk of early recurrence and relatively low risk of late recurrence compared to luminal type breast cancer. Among all subtypes of breast cancer, TNBC is more likely to have BRCA1/2 germline mutation which showed prevalence rate from about 10% to 20% in previous reports. To date, there are only few studies about the effect of BRCA1/2 mutations on the long-term oncologic prognosis in TNBC patients. We analyzed long-term oncologic outcome in unselected TNBC patients according to BRCA1/2 mutations in a comprehensive single institution. Methods Among 11,994 patients who underwent primary breast cancer surgery at Samsung Medical Center (SMC) between June 2008 and January 2016, 1,628 (13.6%) were TNBC patients. Of those, patients with inadequate and unavailable samples at SMC biobank and patients with follow-up duration less than 12 months and who had distant metastasis at presentation were excluded from the study, and 953 patients were enrolled. A retrospective study was conducted and BRCA1/2 genetic testing was done with SMC biobank samples through Next Generation Sequencing (NGS). Results Among 953 unselected TNBC patients, 122 patients (12.8%) had BRCA1/2 mutations: 91 (9.5%) were in BRCA1, and 32 (3.4%) were in BRCA2. One patient had both BRCA1/2 mutations. BRCA1/2 carriers were more likely to have personal history of ovarian cancer (9.0% vs. 0.5%, p < 0.0001), family history of breast cancer and/or ovarian cancer (40.2% vs. 9.4%, p < 0.0001), bilateral breast cancer (4.9% vs. 1.2%, p = 0.0105), and higher nuclear grade (86.0% vs. 74.0%, p = 0.0250). The median follow-up duration was 80.9 months. There were no significant differences in disease-free survival (DFS), distant metastasis-free survival (DMFS), overall survival (OS), and breast cancer-specific survival (BCSS) (p = 0.375, 0.268, 0.413, and 0.133, respectively) between BRCA1/2 carriers and non-carriers. However, BRCA1/2 carriers showed significantly worse contralateral breast cancer (CBC)-free survival than non-carriers (p < 0.0001). Sixty and 120-months cumulative recurrence rate were 18.5% and 31.2% for BRCA1/2 carriers versus 19.3% and 22.7% for non-carriers (p = 0.834 and 0.136, respectively). However, cumulative recurrence rate at 150 months showed absolute but not statistically significant difference between BRCA1/2 carriers and non-carriers (36.2% versus 23.5%, p = 0.080). Cumulative CBC recurrence rate on 60, 120- and 150-months estimates were 6.7%, 18.7% and 25.5% for BRCA1/2 carriers versus 1.1%, 2.7% and 5.2% for non-carriers which showed statistically meaningful difference (p = 0.025, 0.006 and 0.018, respectively). Sixty months, 120- and 150-months cumulative expire rate were 11.2%, 15.6% and 27.7% for BRCA1/2 carriers versus 14.3%, 20.7% and 20.7% for non-carriers (p = 0.319, 0.202 and 0.549, respectively). Discussion In this unselected cohort of patients with TNBC, we found 12.8% (122 patients among 953) prevalence of BRCA1/2 mutations. The median follow-up duration was 80.9 months. There was no significant difference in DFS, DMFS, OS and BCSS by BRCA1/2 mutation status in long-term follow up. However, BRCA1/2 carriers showed significantly worse CBC recurrence rate at 60, 120- and 150- months. And also, BRCA1/2 carriers had 12.7% higher risk of recurrence than non-carriers at 150 months, which was not statistically meaningful but showed absolute difference. Among patients with CBC recurrence, 41.3% (12 patients among 29) were BRCA1 carriers, over 85% had TNBC type of recurred CBC and approximately 80% underwent chemotherapy. In conclusion, we demonstrated that CBC recurrence risk is relatively high in TNBC patients with BRCA1 mutation and showed high chance to receive chemotherapy. Therefore, long-term follow up and appropriate genetic counseling, risk assessment should be done properly for BRCA1/2 mutation carriers in TNBC patients. Citation Format: Soo Yeon Chung, Jai Min Ryu, You Jin Jung, Yeon Jin Kim, Hye Jin Kim, Seok Jin Nam, Seok Won Kim, Jonghan Yu, Byung Joo Chae, Jeong Eon Lee, Se Kyung Lee, Sung-Won Kim, Eun Young Kim. Long-term oncologic outcome of unselected triple-negative breast cancer patients according to BRCA1/2 mutations: a comprehensive single institution study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-03-01.

Introduction Tumor metastasis is a major clinical challenge accounting for the vast majority of cancer related deaths.In previous studies, prediction of distant metastasis was based on subtypes,clinical status and sometimes gene expression were used however clinical application was difficult. In this study, we develop the easy to use prediction tool for distant metastasis using clinical characteristics and gene profiles which came from CancerSCANTM, Next Generation Sequencing based targeted-sequencing platform designed at Samsung Medical Center(SMC). Methods We performed a retrospective chart review of 326 breast cancer patients who underwent surgery and CancerSCAN TM between Jan 2001 and Dec 2014 at SMC. Median follow up period was 83 months (Range 1˜190). Cancer scanTM cover 381 genes but 27 genes and 34 occasions (loss of function, mutation or copy number variation) were selected for analysis through gradient boosting and Wilcoxon Signed rank test. Azure Machine Learning is a cloud service that enables the execution of machine learning processes.This was accomplished using the steps of (1) edit the data, (2) split the data, (3) train the model, (4) score the model, and (5) evaluate the model. We split the modeling data into training and testing sets using a randomized 50–50 split. Two-class Decision Forest method was used. After deploying the Azure ML predictive model as a web service, we used a Representational State Transfer application programming interface to send data and obtained predictions in real-time. Results No distant metastasis group and distant metastasis group consisted of 267 and 59 patients, respectively. HR-/HER2+ and 50 years old and over patients were higher in metastasis group (p-value = 0.003 and p-value = 0.000). Nuclear grade 3 and N2,3 were higher in metastasis group (p-value = 0.010 and p-value = 0.000, p-value = 0.001 respectively). Stage III was also higher in metastasis group (p-value = 0.000). Among 59 patients with distantmetastasis, multiple sites metastasis was 21 cases (35.6%) and then lung metastasis was 19 cases (32.2%). In the 21 cases of multiple sites metastasis, triple sites was 6 cases (28.6%) and double sites was 15 cases (71.4%). PIK3CA mutation was the most frequent gene variation in all patients (34.5% of no metastasis group and 27.1% of metastasis group) but there was no difference between two groups(p-value = 0.278). BRCA 1 loss of function and BRCA2 loss of function were more frequent in metastasis group than no metastasis group(p-value = 0.033 and p-value = 0.024, respectively) but total counts was too small. We assessed the area under the curve (AUC) of the receiver operating characteristic (ROC) curve for predictive value. The AUC of ROC curve was 1.000 and also accuracy, precision, recall were 1.000. In addition, we conducted internal validation using 83 patients during 2015. When we applied a 0.5 threshold value with our predictive model, true negative was 81 and true positive was 2 among 83 patients. Finally, the accuracy of validation was 1.000. Conclusion Our predicted model could represent a useful and easy-to-access tool for the selection of patients with distant metastasis. After additional evaluation with large data and external validation, worldwide use of our model could be expected. Citation Format: Kim I, Choi HJ, Ryu JM, Lee SK, Yu JH, Kim SW, Nam SJ, Seo SW, Lee JE. A predictive model for distant metastasis in breast cancer patients using machine learning [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-52.

Background: There are many factors that might contribute to the delay of surgery in patients with breast cancer. Previous studies investigate the influence of delay of surgery, but they reported inconsistent results. The purpose of this study was to evaluate the impact of time of surgery on prognosis of breast cancer. Methods: We performed a retrospective review of the patients with breast cancer, who received surgery between 1992 and 2009, by using data from Korea Breast Cancer Society Registry. Kaplan-Meier survival analysis and Cox regression model were used to evaluate the impact of time to surgery in breast cancer and subgroup analyses were performed for each disease stage and molecular subtype. Result: A total 14727 patients were included for analysis. Delay of surgery more than 31 days was associated with worse survival for breast cancer [hazard ratio (HR) = 2.16; 95% confidence interval (CI), 1.936-2.408, p Conclusion: Surgical delay of more than 31 days were independent risk factors for worse outcome of breast cancer in each molecular subtype and breast cancer group except stage 0 and I. Although preoperative evaluation is required, surgical delay should be shortened to enhance survival of breast cancer, especially in patients with tumor size more than 2cm or presence of lymph node metastasis. Citation Format: Kim J-M, Choi HJ, Kim I, Ryu JM, Yu J, Lee JE, Kim SW, Nam SJ, Lee SK. The impact of time interval between diagnosis and surgery in each type and stage of breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-29.

Purpose The 21 gene expression assay, Oncotype DX (ODX) is costly (the current estimated cost is ˜$4000), and were tested in only approximately one-third of breast cancer patients who meet the inclusion criteria in the United States. Recent study of University of Tennessee Medical Center reported a novel nomogram for prediction of ODX recurrence score using clinico-pathologic data, which was based on a large dataset from the National Cancer Data Base (NCDB). The purpose of this study was to confirm that the nomogram could predict ODX score group accurately with Korean data, which is different from the NCDB in terms of ethnicity. Methods A retrospective review was performed with 218 patients who received breast-conserving surgery or mastectomy at Samsung Medical Center and were tested with the ODX from April 2011 to January 2017. An online nomogram calculator, provided by the University of Tennessee Medical Center on their website was used in order to calculate the probability of a low-risk or a high-risk ODX score for each patient. The cut-off value for predictive accuracy of the nomogram was set same as the original study. Results With the cut-off value as 90% for inspection of the commercial ODX score, high-risk group showed 33.3% positive predictive value (PPV) and low-risk group showed 68.7%. With the cut-off value as 86% for TAILORx score, PPV was 66.7% for high-risk group, and 38.9% for low-risk group. The sensitivity of the nomogram for the low-risk group commercial ODX score was 96.8%, and 33.3% for the TAILORx score. For the high-risk group, sensitivity was 20% for the commercial ODX score, and 16.7% for the TAILORx score. Conclusions Although the nomogram for prediction of ODX score was based on a large dataset of NCDB, it could not be generalized to patients in Asia. Further studies based on large data from different ethnicities should be performed to develop the nomogram for patients worldwide. Citation Format: Kim J-M, Ryu JM, Kim I, Choi HJ, Nam SJ, Kim SW, Yu J, Lee SK, Lee JE. The accuracy of nomograms based on large dataset using clinico-pathologic variables for prediction of oncotype DX breast cancer recurrence score [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-11-01.

Breast cancers (BC) in younger, premenopausal patients (YBC) tend to be more aggressive with worse prognosis, higher chance of relapse and poorer response to endocrine therapies compared to breast cancers in older patients. The proportion of YBC (age ≤ 40) among BC in East Asia is estimated to be 16-32%, significantly higher than the 7% reported in Western countries. To characterize the molecular bases of Asian YBC, we have performed whole-exome sequencing (WES) and whole-transcriptome sequencing (WTS) on tumor and matched normal samples from 134 Korean BC patients consisting of 74 YBC cases (age ≤ 40) and 60 OBC cases (age > 40). We then performed comparison analyses and integrative analyses with the TCGA BC cohort consisting of 1,116 tumors from primarily Caucasian patients, also grouped by age into YBC (age ≤ 40), IBC (40 < age ≤ 60) and OBC (age > 60). Somatic mutation prevalence analysis identified 7 significantly mutated genes and the same top three genes – TP53, GATA3 and PIK3CA – were reported by the TCGA BC study. To identify differentially expressed (DE) genes and pathways in YBCs vs. OBCs, we performed logistic regression analyses while controlling for the confounding effects of tumor purity and stage. We were surprised to see a significant overlap in DE pathways between a comparison of adjacent normal tissues in younger vs. older TCGA cohorts and a comparison of YBC vs. OBC tumors, indicating that normal tissue compartment could contribute to observed differences between bulk tumors. To separately examine molecular signatures from tumor, stroma and normal compartments, we used non-negative matrix factorization (NMF) analyses to virtually dissect bulk tumor expression data and identified 14 factors including 3 factors associated with normal tissues, 1 factor associated with stroma and 1 factor associated with tumor infiltrating lymphocytes (TIL). Integrative analyses of tumor associated factors and DE pathways revealed that estrogen response, endocrine therapy resistance, and oxidative phosphorylation pathways are up-regulated in YBCs compared to OBCs while cell cycle and proliferation pathways are up-regulated in Asian OBCs. Interestingly, many immune and inflammation pathways correlated with the TIL factor were significantly upregulated in OBCs vs. YBCs. Using gene expression signatures representing distinct immune cell types, we classified our cohort into four subtypes of varying TIL activities and observed significant enrichment of the TIL-high subtype in OBCs compared to YBCs. These observations were confirmed by IHC analyses of four TIL markers (CD45, CD4, CD8 and CD163) in 120 tumors. To our knowledge, this is the first large-scale multi-omics study of Asian breast cancer and would significantly contribute to the compendium of molecular data available for studying young breast cancers. The major landmarks in the molecular landscape looked similar across BCs of different ethnicities and ages, however, we have identified a number of distinguishing molecular characteristics associated with Asian YBC. The sources for some signatures were further traced to non-tumor intrinsic compartments, indicating that tumor microenvironment may play potentially important roles in driving the carcinogenesis of young breast cancers. Citation Format: Kan Z, Ding Y, Cho S, Lee S-H, Powell E, Jung HH, Chung W, Deng S, Choi Y-l, Kim J, Park W-Y, Vizcarra P, Fernandez-Banet J, Nichols T, Ram S, Lee SK, Kim SW, Lee JE, Ching KA, Kim J-Y, Ahn JS, Im Y-H, Nam SJ, Park YH. Multi-omics and immuno-oncology profiling reveal distinct molecular signatures of young Asian breast cancers [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-05-15.

Purpose: Crosstalk between growth factor receptor tyrosine kinases (RTKs) and the estrogen receptor (ER) represents one of the most important mechanisms of endocrine resistance. EGFR and HER2 have been recognized as prominent factors associated with endocrine resistance. Most previous studies did not identify subgroups by HER2 overexpression and/or included breast cancer with HER2 overexpression. Accordingly, we analyzed HR positive (HR+) tumors without HER2 overexpression (HER2-). Methods: We analyzed the clinical data of 2,166 patients with HR+HER2- breast tumors, between January 2007 and July 2013.We included only patients who had endocrine therapy with tamoxifen. Immunostaining for EGFR was interpreted as positive when at least 10% of the tumor cells showed moderate to strong membrane staining. Results: EGFR expression (EGFR+) was present in 109 patients (5%). EGFR expression was significantly associated with more advanced stage and higher grades. In the univariate analyses, EGFR+ tumors were associated with poorer prognosis than EGFR- tumors (5-year DFS, EGFR+ vs. EGFR-, 91.2% vs. 96.6%, P Conclusion: EGFR expression could be prognostic factor in hormone receptor-positive and HER2 negative breast cancer, for tamoxifen resistance. Citation Format: Bae SY, Nam SJ, Lee SK, Kim SW, Lee JE, Yu JH. Tamoxifen resistance: EGFR expression in hormone receptor-positive and HER2 negative breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-09-36.

Background: Triple-negative breast cancer (TNBC) consists of heterogeneous sub-population. Although many investigators made an effort to categorize and classify TNBCs using genetic expressions, it is still needed to be defined for prognostication Traditionally, HER family genes have been known to contribute mammalian glands formation and breast cancer generation as well as ESR gene. Moreover, target agents for HER family genes have been already developed. Accordingly, we investigated the expression profiles of HER family genes with ESR in patients with TNBC to categorize into sub-types and determine the prognostic value of HER family genes in search of clinical implications. Methods : We investigated the results of the nCounter expression assay (NanoString®) for ERBB1, ERBB2, ERBB3, ERBB4 and ESR1 using mRNA extract from paraffin-embedded tumor tissues in 203 patients diagnosed as TNBC. We used the results of nCounter expression assay using 84 TNBC tissues for validation and 52 breast cancer tissues diagnosed as other subtypes to control the expression assay results of these five genes. Results: Two-hundred and three patients were diagnosed as TNBC from 2000 to 2004 and received adjuvant chemotherapy after curative surgery. Eighty-four TNBC patients for validation set and 52 patients diagnosed as other subtypes for control set were selected from the patients diagnosed as breast cancer from 2005 to 2010 and received curative surgery. Through analyzing 5 genes using the nCounter expression profiles from 203 TNBC tissues, we found that increased expression of ERBB4 was associated with poor prognosis by survival analysis (5 year disease recurrence free survival (DRFS), low vs. high expression [cut-off: median]: 90.1% vs. 80.2%; p =.002). This trend was still remained in validation set composed of TNBC (5 year DRFS, low vs. high expression [cut-off : median]: 61.1% vs. 44.0%), whereas was not observed in other subtypes of breast cancer (44.4% vs. 80.8%). The Kaplan-Meier estimates of the rates of 5 year DRFS in the subgroups classified according to the level of 5 genes expression showed that the group of higher expression of all HER family genes and lower expression of ESR1 gene had dismal prognosis rather than other groups in patients with TNBC (5 year DRFS, this group vs. others: 50.0% vs. 88.2%; p Impact of the m RNA expression levels of ERBB family and ESR1 on DRFS Hazard Ratio95% CIP-valueStage Conclusions: The expression profile of HER family genes could be used as a prognostic marker in patients with TNBC. Further study is needed to identify the expression profiles of HER family gene as predictive marker of HER targeting treatment in patients with TNBC. Citation Format: Kim J-Y, Ahn T, Jung HH, Park K, Do I-G, Kil WH, Kim SW, Lee JE, Nam SJ, Ahn JS, Park YH, Im Y-H. Prognostication of HER family gene expression collaborate with ESR1 expression in patients with triple negative breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-08-19.

Purpose The results of the Suppression of Ovarian Function Trial (SOFT) and the Tamoxifen and Exemestane Trial (TEXT) showed that ovarian function suppression (OFS) in premenopausal early breast cancer patients improves disease control. However, mood swings after OFS is one of the chief complaints to make patients stop undergoing endocrine therapy. Studies about complications of OFS in breast cancer patients are not established well. We designed this randomized controlled trial to evaluate psychological functioning of patients after undergoing adjuvant OFS by goserelin. Patients and Methods We randomly assigned 64 premenopausal women with hormone receptor positive early breast cancer to the tamoxifen or tamoxifen plus goserelin group for a period of 1 year. Participants were screened for depression and generalized anxiety disorder using Hamilton Rating Scale for Depression (HAMD), Hamilton Rating Scale for Anxiety (HAM-A), Anxiety Sensitivity Index (ASI) and Albany panic and phobia questionnaire (APPQ) at baseline, 6 months and 12 months. Brain-derived Neurotrophic Factor (BDNF) levels were measured, as well. The results were analyzed by using a linear mixed model and a generalized linear mixed model. Results Thirty two patients were distributed in each group, equally. Linear mixed-mixed model analyses revealed that, compared with HAM-A scores of each group at baseline, HAM-A scores at 12 months showed increments (p=0.0078). Among HAM-A questions, Questions for intellectual, sensory and autonomic status were scored significantly high at 12 months (p=0.0018, p=0.0132, p=0.0006). Platelet BDNF levels reported a statistically significant rise at 12 months (p=0.0006). There was no significant time-by-study group effect in all scales. Conclusion Compared with the patients without OFS, patients with Goserelin showed no difference in anxiety or depression scales. Thought the levels of anxiety of each group at 12 months were increased, they do not indicate medical interventions. Patients with increased levels of BDNF at 12 months are expected to have good recovery from anxious and depressive symptoms. Citation Format: Yi HW, Nam SJ, Kim SW, Lee JE, Lee SK, Bae SY, Park S, Paik H-J, Ryu JM. Depression and anxiety after adjuvant ovarian function suppression in premenopausal breast cancer patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-11-01.

Background: The MRE11-RAD50-nibrin (MRN) complex participates in pathways of double-strand break induced DNA repair and cell cycle checkpoint control. RAD50 interacts with the MRE11 and NBS proteins, is involved in the maintenance of genomic integrity. The association of RAD50 mutation and breast cancer susceptibility has been reported in European patients. However, the impact of RAD50 mutation on a breast cancer predisposition among Koreans remains uncertain. In the current analysis, we evaluated the incidence of RAD50 mutations among Korean patients with non-BRCA1/2 high-risk breast cancer. Materials and Methods: A total of 247 Korean patients with high-risk breast cancer who tested negative for BRCA1/2 mutation were enrolled. The criteria for high-risk breast cancer were as follows: having a family history of breast or ovarian cancer in any relative; diagnosed at age 40 years or younger; bilateral breast cancer; and male breast cancer. All participants were screened for BRCA1/2 mutations using fluorescent-conformation sensitive capillary electrophoresis (F-CSCE) and traditional sequencing. The entire RAD50 gene of each patient was sequenced using F-CSCE. In silico analyses of the RAD50 variants was performed using PolyPhen-2 and SIFT. Results: There were two novel deleterious mutations in RAD50 (p.Q426X, p.E1271del). These mutations were found in two patients, including one with p.Q426X and the other with p.E1271del. Besides, five sequence variants in RAD50 were identified: four exonic variants (p.I118T, p.R486C, p.L1264F, and p.R1279H) and one intronic variant (c.1246-11T>C). Among the four missense variants, p.R486C and p.L1264F were variants predicted to be deleterious by in silico analyses. Conclusions: We found protein-truncating mutations in RAD50 gene in a small proportion of Korean patients with high-risk breast cancer. The contribution of the mutation to the development of breast cancer should be clarified in further researches. Citation Format: Kim H, Cho D-Y, Choi DH, Jung GH, Shin I, Park W, Huh SJ, Nam SJ, Lee JE, Gil WH, Kim SW. Heterozygous germline mutations in RAD50 among Korean patients with high-risk breast cancer negative for BRCA1/2 mutation. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-08-08.

Background/Aims: Despite effective therapeutic strategies for treating hormone receptor-positive (HR+) breast cancer, resistance to endocrine therapy that is either de novo or acquired still occurs. We investigated epidermal growth factor receptor (EGFR) as a therapeutic target for overcoming endocrine resistance in HR+ breast cancer models. Methods: Using clinical data from 2,166 patients who had HR+ breast tumors and received tamoxifen, we analyzed survival rates. Levels of mRNA and protein expression were analyzed by real-time PCR and western blotting, respectively. Cell viability was analyzed by MTT assays and anchorage-independent growth by soft agar colony-formation assays. Efficacy of tamoxifen and/or gefitinib was analyzed using orthotopic xenograft mouse models. Results: EGFR expression was significantly associated with more advanced stage and higher grade. EGFR expression was different in luminal A-like (Lum A, 1.3%) versus luminal B-like (Lum B, 11.4%) subtypes. On multivariate analyses for survival Lum B subtype EGFR+ tumors showed a hazard ratio (HR) of 5.22 (95% CI, 1.29-21.15, P = 0.020) for overall survival (OS) and HR of 2.91 (95% CI, 1.35-6.28, P = 0.006) for disease-free survival (DFS). Levels of EGFR inversely correlated with ER-α expression. Basal ER-α level was completely blocked by TGFA or EGF treatment. With TGFA pretreatment, ER+ breast cancer cells were resistant to 4-hydroxytamoxifen (4-OHT). Conversely, downregulation of ER-α by TGFA was reversed by gefitinib with recovered sensitivity to 4-OHT. Tumorigenicity of EGFR and ER+ breast cancer cells was significantly decreased by combined tamoxifen and gefitinib. Conclusion: Aberrant EGFR expression was associated with poor prognosis in ER+ breast cancers, especially the Lum B subtype. Loss of ER by EGFR activation induced tamoxifen resistance. Therefore, EGFR could be a therapeutic target for overcoming recurrence of ER+ breast cancer with high EGFR expression. Citation Format: Yisun Jeong, Soo Youn Bae, Daeun You, Seung Pil Jung, Hee Jun Choi, Isaac Kim, Se Kyung Lee, Jonghan Yu, Seok Won Kim, Jeong Eon Lee, Sangmin Kim, Seok Jin Nam. Epidermal growth factor receptor as therapeutic target in hormone receptor-positive breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-04-25.

BACKGROUND: Women with triple-negative breast cancers (TNBCs) represent a significant treatment challenge as they have a relatively poor prognosis and no effective targeted therapy exists. Although TNBCs are often discussed as a single disease entity of breast cancers, in fact they are very heterogeneous. The aim of this study was to investigate candidate genes that might function as biomarkers to differentiate TNBCs among patients, who received adjuvant chemotherapy after curative surgery, into those with high or low risk for distant recurrence. METHODS: We tested whether the results of a NanoString expression assay that targeted 245 prospectively selected genes and used mRNA extracted from paraffin wax-embedded tumor tissues would predict distant recurrence in patients with TNBC. The levels of expression of seven genes were used in a prospectively defined algorithm to allocate each patient to a risk group (low or high). RESULTS: NanoString expression profiles were obtained for 203 tumor tissue blocks. Increased expressions of the five genes (SMAD2, HRAS, KRT6A, TP63, and ETV6) and decreased expression of the two genes (NFKB1 and MDM4) were associated favorable prognosis in this patients’ cohort and were validated with cross-validation. The proportions of patients categorized as having low or high risk were 75% and 25%, respectively. The Kaplan–Meier estimates of the rates of distant recurrence at 10 years in the low- and high-risk groups according to gene expression signature were 62% (95% CI, 48.6–78.9%) and 85% (95% confidence interval, CI, 79.2–90.7%), respectively. When adjusting for tumor–node–metastasis (TNM) stage, the distant recurrence-free survival (DRFS)s in the low-risk groups were significantly longer than that in the high-risk group (p CONCLUSION: A seven-gene signature could be used as a prognostic model to predict DRFS in patients with TNBC who received curative surgery followed by adjuvant chemotherapy. Citation Format: Yeon Hee Park, Hae Hyun Jung, In-Gu Do, Eun Yoon Cho, Insuk Sohn, Sin-Ho Jung, Won Ho Kil, Seok Won Kim, Jeong Eon Lee, Seok Jin Nam, Jin Seok Ahn, Young-Hyuck Im. A seven-gene signature can predict distant recurrence in patients with triple-negative breast cancers (TNBCs) who receive adjuvant chemotherapy following curative surgery of the primary breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-06-20.

BACKGROUND: Neoadjuvant chemotherapy (NAC) has been used widely in patients with locally advanced breast cancer (LABC). NAC has the added advantage of increasing breast conservation rates with similar disease-free and overall survival compared with adjuvant chemotherapy. A subset of patients receiving NAC experiences early failure during the course of therapy or within a short period after breast surgery. There are no established predictors for early therapy failure in LABC patients who received NAC. This study was performed to identify candidate actionable mutation to explain early failure and refractoriness to chemotherapy in BC patient groups that may not benefit from NAC. METHODS: Seventy eight patients among 397 Patients with LABC (cT2-4N0-3) who were available for preoperative FFPE tumor block for next generation sequencing (NGS) included in this analysis excluding 21 patients whose FFPE were not qualified for Ampliseq. Early failure was defined as the development of an inoperable state caused by locoregional or systemic progression during NAC or relapse after curative surgery within 1 year after the initiation of NAC. Patients who developed recurrence after 1 year from the start of NAC or exhibited no failure during the follow-up period were defined as control in this study. Thus, our cohort was composed of pCR (pathologic CR to NAC), early failure, and control. The clinicopathological characteristics and disease courses of the patients whose disease progressed within 1 year of receiving neoadjuvant chemotherapy were analyzed to compare with the other patients. Using the Ion Torrent Ampliseq Cancer Panel v2 after DNA isolation from FFPE samples, we sequenced 2,855 loci from 50 cancer-related genes to identify genetic mutations in 78 BC patients who received NAC for patients with locally advanced BCs and available preoperative tumor tissue. RESULTS: Thirty-eight of the 397 patients (9.6%) exhibited progression within 1 year after receiving neoadjuvant chemotherapy. Among 78 patients who were available tumor tissue in this analysis, the number of patients with early failure, pCR, and control was 22, 19, and 27, respectively. The sequencing analysis revealed TP53 mutations were observed in 95% or more patients, evenly irrespective of patients’ group. Missense mutations in ALK and BRAF were found to be predominantly much higher in patients with early failure than in other groups (p CONCLUSION: ALK and BRAF genes are associated with early failure in this analysis. Our results support that targeted sequencing using cancer panel may function to identify actionable targets which are associated with responsiveness to NAC for patients with LABC. Further research to figure out the functioning role of these genes for each group is warranted. Citation Format: Yeon Hee Park, Moon Ki Choi, In-Gu Do, Eun Yoon Choi, Won Ho Kil, Seok Won Kim, Jeong Eon Lee, Seok Jin Nam, Jin Seok Ahn, Young-Hyuck Im. ALK and BRAF genes are associated with early failure of breast cancer (BC) who received primary neoadjuvant chemotherapy for patients with locally advanced BCs [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-06-44.

Overexpression of p53 is the most frequent genetic alteration in breast cancer. Recently, many studies have shown that the expression of mutant p53 differs for each subtype of breast cancer and is associated with different prognoses. In this study, we aimed to determine the suitable cut-off value to predict the clinical outcome of p53 overexpression and its usefulness as a prognostic factor in each subtype of breast cancer, especially in luminal A breast cancer. Approval was granted by the Institutional Review Board of Samsung Medical Center. We analyzed a total of 7739 patients who were surgically treated for invasive breast cancer at Samsung Medical Center between Dec 1995 and Apr 2013. Luminal A subtype was defined as ER&PR + and HER2- and was further subclassified according to Ki-67 and p53 expression as follows: luminal A (Ki-67-,p53-), luminal A (Ki-67+, p53-), luminal A (Ki-67 -, p53+) and luminal A (Ki-67+, p53+). Low-risk luminal A subtype was defined as negative for both Ki-67 and p53 (luminal A (ki-67-, p53-)), and others subtypes were considered to be high-risk luminal A breast cancer. A cut-off value of 10% for p53 was a good predictor of clinical outcome in all patients and luminal A breast cancer patients. The prognostic role of p53 overexpression for OS and DFS was only significant in luminal A subtype. The combination of p53 and Ki-67 has been shown to have the best predictive power as calculated by the area under curve (AUC), especially for long-term overall survival. Table 1. Factors associated with overall survival in luminal A subtype breast cancer patients (N=3918). Univariable Multivariable* Factors HRP-value95% CI for HRHRP-value95% CI for HRBreast surgery TM- (ref.)- (ref.)- (ref.) BCS0.4430.03180.211-0.932 Presence of LVI No- (ref.)- (ref.)- (ref.) Yes4.783 In this study, we have shown that overexpression of p53 and Ki-67 could be used to discriminate low-risk luminal A subtype in breast cancer. Therefore, using the combination of p53 and Ki-67 expression in discriminating low-risk luminal A breast cancer may improve the prognostic power and provide the greatest clinical utility. Citation Format: Ha Woo Yi, Se Kyung Lee, Soo Youn Bae, Jun Ho Lee, Hyun-Chul Lee, Won Ho Kil, Jeong Eon Lee, Seok Won Kim, Seok Jin Nam. Ki-67 and p53 are useful factors to predict long term survival in low-risk luminal A breast cancer patients [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P4-11-43.

The molecular bases underlying neoadjuvant chemotherapy (NAC) response are poorly understood. To elucidate the effects of NAC on breast tumor biology and its association with clinical outcome, we have conducted WES and RNA-Seq profiling of a longitudinal breast cancer (BC) cohort consisting of 146 cases (281 tumors, 109 pairs), including 55 (38%) that achieved pathologic complete responses (pCR) and 91 (62%) that harbored residual diseases at time of surgery. Tumor biopsies were collected for each patient at three time points - pre-treatment, three weeks after the first cycle of anthracycline and cyclophosphamide (AC) and at the time of surgery, after 3 more cycles of AC followed by 4 cycles of taxane. In addition to somatic mutations and copy number alterations, we also derived a comprehensive set of genomic and molecular features for each tumor including chromosomal instability, loss-of-heterozygosity, mutation burden, mutation signatures and expression signatures for oncogenic signaling pathways and immune cell subsets. Virtual microdissection analysis inferred 14 factors that represent distinct tissue compartment including a tumor infiltrating lymphocyte (TIL) factor and revealed that initial NAC treatment increased stromal and adjacent normal tissue fractions while reducing tumor cellularity. NAC also induced dynamic changes in immune gene expressions over time, a pattern that was validated through detecting and quantifying the density of TILs from H&E images. To investigate NAC induced changes in tumor intrinsic biology we classified tumors into five oncogenic cellular states on a reference Onco-GPS map defined by transcriptional signatures from breast cancer cell lines. We observed that, as a result of NAC treatment, tumors often change from one oncogenic state to another, transiently upregulating an EMT program that appears to mediate drug resistance and increase the likelihood of residual disease. Multiple regression and multivariate analyses were performed to identify predictive biomarkers of pCR status while adjusting for BC subtypes and tumor purity. We found that ER+ subtype and estrogen response signature but not Ki-67 were independently associated with NAC response. Within TNBC, the immunomodulatory subtype was enriched in responders while the basal-like subtype had the poorest response. Pretreatment TIL and changes in TIL level over time were independently associated with NAC response, implicating anti-tumor immunity in mediating the efficacy of chemotherapies. Through multi-omics characterization of longitudinally paired tumor biopsies, we have revealed dynamic changes in the tumor molecular states in BC patients undergoing NAC treatment, identified molecular markers of treatment outcome and derived insights into the mechanism of action as well as resistance to an important class of therapy. Citation Format: Samir Lal, Ying Ding, Jeong Eon Lee, Soo-Hyeon Lee, Se Kyung Lee, Jae-Yong Nam, Jong Han Yu, Yoon-la Choi, Seok Won Kim, Seok Jin Nam, Ji-Yeon Kim, Sripad Ram, Eric Powell, Keith A. Ching, Pablo Tamayo, William Kim, Huwate Yeerna, Soo Youn Cho, Vinicius Bonato, Shibing Deng, Jinho Kim, Hyuntae Shin, Woong-Yang Park, Paul A. Rejto, Jadwiga Bienkowska, Yeon-Hee Park, Zhengyan Kan. Multi-omics profiling of breast cancers during neoadjuvant chemotherapy identified distinct molecular changes and biomarkers associated with clinical response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1684.

Background and Purpose In several breast cancer analyses of targeted gene panels, there was considerable concordance of mutations observed between primary tumors and matched metastases. We are to investigate to gain an understanding of the underlying genetics leading to BC metastasis to compare genomics data using paired biopsies between primary breast and several metastatic sites. Methods We performed CancerSCANTM of forty-eight patients with paired primary and metastatic tumors, which is 380-gene targeted panel sequencing using HiSeq 2500 sequencing platform (Illumina). We made variant calls using Mutect for SNV, Pindel for INDEL, Contra for CNV, and in-house software for Fusion with default parameters. Tumor mutational burden (TMB) was measured by number of mutations per megabase (mb), and TMB was divided into two groups: high TMB (>=20mutations/mb) and low TMB ( Results Seven among 48 patients (14.6%) showed discordant subtypes between primary and metastatic tumors, discordant patterns were diverse. Lung and pleural was the most frequent organ in metastatic tumors, and liver and lymph node were followed. There were 15 shared, 6 primary-specific, 4 metastatic-specific mutations per patient on average, and no significant difference in overall survival (OS) with respect to mutation-sharing patterns. TMB and number of mutations related to mismatch-repair (MMR) genes such as NF1 (P=0.0398) and PMS2 (P=0.1020) tended to be reduced in metastatic tumors compared to paired primary tumors. Mutational signature 3 (BRCA1/2) was increased in metastatic tumors, and signature 5 (General Cancer) was decreased (P>0.05). defect in MMR genes (P=0.0445) and germline BRCA mutation (P=0.0186) were significantly associated to OS, but TMB status, and mutational signature related to MMR respectively were not significant variables for OS according to the molecular profiles in primary tumors. Patients with PMS2 (P=0.156) and NF1 (P=0.0734) multi-hit mutations were better prognosis. Combining molecular profiles in primary tumors such as TMB and mutational signature 6 (MMR) and signature 13 (APOBEC) showed significant differences in OS: low TMB with high signature 6 plus 13 as worse, high TMB as intermediate, and low TMB with low signature 6 plus 13 as better prognosis (P=0.0228). Conclusions With the combination of TMB and MMR-related molecular profiles, we could stratify patients into three groups according to OS. Citation Format: Kyung Hee Park, Eunjin Lee, Seri Park, Se Kyung Lee, Seok Won Kim, Jeong Eon Lee, Seok Jin Nam, Ji-Yeon Kim, Hee Kyung Ahn, Woong-Yang Park, Yeon Hee Park. Analysis of the targeted sequencing with RNA Seq. results between primary breast cancer and metastatic sites: Matched paired analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2520.

Background: Inflammation is a key regulatory process in breast cancer progression and severity. Several studies have demonstrated that prolonged exposure of breast tumor cells to inflammatory cytokines leads to epithelial-mesenchymal transitions (EMT), which is the principle mechanism involved in metastasis and tumor invasion. Disruption of the signaling pathways involved in EMT may therefore provide an effective treatment strategy for currently difficult to treat or untreatable cancers such as TNBC. The interleukin (IL)-1 plays a pivotal role on breast cancer proliferation, invasion and/or inflammation. Here, we investigated the correlation of MMP-3 and IL-8 on IL-1b-induced cell migration and invasion as well as the inhibitory effect of zerumbone on IL-1β-induced MMP-3 and IL-8. Methods: Triple negative breast cancer cells (Hs578T and MDA-MB231) were cultured DMEM with 10% FBS and 1% antibiotics. The levels of IL-8 and MMP-3 mRNA were analyzed by real-time PCR. The levels of secreted IL-8 and MMP-3 protein expression were analyzed by ELISA and western blot analysis, respectively. Cell viabilities by drug were analyzed by MTT assay. Cell invasion and migration was detected by Boyden chamber assay. Results: The level of IL-8 and MMP-3 mRNA and protein expression significantly increased by IL-1β treatment in both Hs578T cells and MDA-MB231 cells. In addition, IL-1β-induced cell migration and invasion also increased in Hs578T and MDA-MB231 cells. On the other hand, the levels of basal and IL-1β-induced IL-8 and MMP-3 expression were decreased by zerumbone. Conclusion: IL-1β induces the migration and invasion of breast cancer cells through IL-8 and MMP-3 expression. These effects are significantly suppressed by zerumbone. Therefore, we suggest that zerumbone may act as a useful therapeutic agent for treatment of triple negative breast cancer. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-09-19.

Background: Endocrine therapy has dramatic improvements of prognosis in patients with hormonal receptor positive breast cancer. However, long-term follow up shows that endocrine resistance is still major clinical concern. Although the value of estrogen receptor (ER) level can predict response to endocrine treatment in hormonal receptor positive breast cancers, few markers are available that can predict response to endocrine treatment. We attempted to identify molecular markers, especially progesterone receptor (PR), associated with endocrine failure in breast cancer. Methods: We reviewed the medical records of 2513 breast cancer patients who underwent breast surgery and endocrine therapy at Samsung Medical Center between March 2007 and July 2011. Patients were compared according to ER and PR expression and to assess the clinical and biological features of ER+positive/PR-negative breast cancers to understand how PR might be a useful marker of these activities. ER and PR expression accessed using Allred score, the ‘positive” was defined that total score is larger than 2. Results PR negative tumors were found more frequently in postmenopausal women (post- 11.2% vs. pre- 2.5%, P < 0.001) and PR negative tumors were significantly associated with higher grade, higher level of Ki 67 and more expression of EGFR and CK5/6. In Kaplan-Meier analysis and multivariate analysis, PR negativity was significantly poorer prognostic factor of DFS (HR 3.1, 95% CI 1.2-8.2, P = 0.021) and OS (HR 89.8, 95% CI 3.4-2352.3, P = 0.007). Stratified by the menopausal status, there was not shown significant difference of survival between the PR+ and PR- tumor in postmenopausal women (DFS, HR 2.1, 95% CI 0.4-10.8, P = 0.381; OS, HR 10.6, 95% CI 0.6-171.4, P = 0.096). However, PR negative tumors showed an association with poor outcome in premenopausal women (DFS, HR 7.2, 95% CI 2.5-20.6, P Conclusion: In HR positive breast cancers, PR negative tumors were found more frequently in elderly, postmenopausal women. However, PR negative tumors are shown more aggressive and poorer survival than PR positive tumors despite of endocrine therapy, especially in premenopausal women. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-09-17.

Background: The aim of the study was to determine factors and develop the model that predict the risk of invasion in patients with ductal carcinoma in situ (DCIS) diagnosed by preoperative biopsy. Methods: We selected 497 patients underwent surgical treatment for preoperatively diagnosed DCIS of the breast between 1997 and 2009. Multivariate analysis was used to identify relevant clinical, radiological and pathological factors that may predict upstaging. A prediction model was developed based on significant factors and measured using the area under the receiver operating characteristics (ROC) curve. This prediction model was subsequently validated using the dataset of 149 cases who were diagnosed with DCIS preoperatively between 2010 and 2012. Results: Of 24.75%, there was an upstaging to the invasive cancer. We found that larger size (≥1.5cm) of DCIS was most significant factor, followed by palpable lesion on physical examination, no expression of estrogen receptor (ER)/progesterone receptor (PR), high nuclear grade, non-cribriform subtype and absence of necrosis significantly associated with presence of invasion. The prediction model with these factors showed that excellent predictive accuracy (the area under the ROC curve= 0.851, 95% CI: 0.817–0.881) and showed similar findings in the validation data set (AUC = 0.868, 95% CI: 0.800–0.916). After ranking the significant factors, we selected 4 factors to simplify the model. This simple model also showed good prediction power (AUC = 0.821, 98% CI: 0.784–0.854). Conclusion: We developed the prediction model to predict upstaging in patients diagnose with DCIS preoperatively based on 4 most significant factors. By this prediction model, we suggest the axilla exploration with SLNB in case of DCIS with more than 1.5 cm size, palpable lesion, no expression of HR and high NG to avoid 2nd operation. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-10-41.

Purpose: Male breast cancer (MBC) is extremely rare, accounting for less than 1% of all malignancies in men and only 1% of all breast carcinomas. The treatment and surveillance guidelines on male breast cancers are less recognized. The aim of this study is to evaluate our single institution's experience with MBC over the past 15 years and to contrast differences between female and MBC. Methods: MBC diagnosed from 1994 to 2010 at the Department of Surgery, Samsung Medical Center (Seoul, Korea) was retrospectively analyzed. Clinical data and tumor characteristics were examined. Each MBC was matched with female counterparts by 1:N varied matching ratio that showed accordance in seven variables (year of diagnosis, age, tumor stage, nodal stage, tumor grade, estrogen receptor(ER), progesterone receptor(PR)). Results: 39 male/184 female matched-pairs were available for analysis. The median duration of follow-up was 3.8 years. The median age of MBC patients was 50 years and the median size of tumor was 2.0cm. The proportion of positivity of ER and PR status was 97.4% and 84.6%, respectively. Despite of higher positive rate of hormone receptor, the rate of hormone therapy in MBC patients was significant lower than female conterpart (p = 0.002). Men and women with breast cancer had similar disease-free survival (DFS) and disease-specific overall survival (DSS). Five MBC patients had a recurrence during follow up period and 4 of them were expired. The 10-years DFS was 73.1% in men and 80.5% in women (p = 0.348). The 10-years DSS was 74.1% in men and 87.1% in women, respectively (p = 0.207). Conclusion: This study showed no disease free and overall survival differences between male and female breast cancer patients and revealed that gender is no predictor for survival in breast cancer. Male patients receive obviously less adjuvant treatment compared their female matched patients. It would be better to do more aggressive treatment in MBC to improve the survival outcome. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-11-01.

Background: Crosstalk between growth factor receptor, especially the EGFR/HER2 pathway, and ER pathways has been associated with endocrine resistance. Thus, combination therapy targeting both ER and EGFR/HER2 signaling to block the crosstalk between these pathways and eliminate escape routes have been proven effective in both preclinical and clinical models. Anti-HER2 directed therapy has been reported to restore hormone sensitivity in HER2−positive breast cancers. Adding trastuzumab to conventional treatment has been a standard treatment of choice in HER2−positive breast cancer irrespective of hormonal receptor (HR) status. The purpose of the study is to evaluate adding effect of 1 year of trastuzumab to conventional adjuvant treatment in patients with HER2−positive breast cancer who received surgery according to HR status. Patients and Methods: We retrospectively analyzed the clinicopathologic characteristics and outcomes of 618 postoperative HER2−positive breast cancer patients between 2001 and 2008 at the Samsung Medical Center. Most of HER2−positive patients in our institute were treated with 1 year of trastuzumab as a part of adjuvant therapy since 2007 (post-trastuzumab era) compared with 2000–2006 (pre-trastuzumab era). Clinical outcomes including recurrence-free survival (RFS) were analyzed between pre-trastuzumab and post-trastuzumab era according to HR status. We performed Cox regression multivariate analysis for relapse using variables from univariate analysis by log-rank test for relapse. Clinical presentations and clinicopathologic characteristics were evaluated at the time of recurrence between both eras. Results: The median age at diagnosis was 46 years (range, 22–79). During the median 60.0 months of follow-up, the 5-year recurrence rate was 20.2%. The 618 patients were divided into two groups (patients who received (n=175) and did not receive (n=443) adjuvant trastuzumab). Recurrence rate was much lower in post-trastuzumab era than in pre-trastuzumab era (13.6% vs. 32.3%, p Conclusion: Cross-talk between ER and EGFR/HER2 pathways may mitigate trastuzumab effect in HER2+ve/ER+ve breast cancers. Further study is warranted. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-12-15.

Purpose Ipsilateral Breast Tumor Recurrence(IBTR!) 2.0 is web-based tool which predict the ten years risk of local recurrence after breast conserving theraphy. This tool integrates seven prognostic factors (patient age, margin status, lymphovascular invasion, tumor size, tumor grade, use of chemotherapy and hormonal therapy) for local recurrence with or without radiation theraphy. To validate IBTR! 2.0 for Korean breast cancer patients, Samsung Medical Center database was used between 1994 and 2001. Methods The IBTR! 2.0 nomogram was tested against 358 patients who underwent breast conserving surgery with radiation theraphy from Samsung Medical Center between 1994 and 2001. The individual dadabase which was entered into IBTR! 2.0 computer model generate predictive local recurrence rate. The mean predicted and observed 10-year estimates were compared for the entire cohort and for four groups predefined by nomogram-predicted risks: group 1: less than 3%; group 2: 3% to 5%; group 3: 5% to 10%; and group 4: more than 10%. Results IBTR! version 2.0 predicted an overall 10-year IBTR estimate of 5.5% (95% CI, 5.2 to 5.9), while the observed estimate was 7.69% (20 IBTR cases in 358 patients, 95% CI, 1.6 to 9.3; P=0.59). The predicted and observed IBTR estimates were: group 1 ( 2 cases in 67 patients): 2.3% versus 2.9%, P=0.53; group 2 (2 cases in 124 patients)): 3.9% versus 4.1%, P=0.18; group 3 (14 cases in 139 patinets): 7.3% versus 4.8%, P=0.13; and group 4 (2 cases in 28 patients): 12.15% versus 7.1%, P=0.61. Conclusion IBTR! 2.0 is acceptable nomogram for predicting 10 years local recurrence using Samsung medical Center database. This nomogram showed overestimation in group 3, 4, however did not showed statistical differences. This nomogram may assist patient counseling and medical decision making, but prior to using whole Korean patients, this model requires validation with multiple Korean sources. References 1. Fisher, B., et al., Twenty-year follow-up of a randomized trial comparing total mastectomy, lumpectomy, and lumpectomy plus irradiation for the treatment of invasive breast cancer. N Engl J Med, 2002. 347 (16): p. 1233–41. 2. Liljegren, G., et al., 10-Year results after sector resection with or without postoperative radiotherapy for stage I breast cancer: a randomized trial. J Clin Oncol, 1999. 17 (8): p. 2326–33. 3. Anderson, S.J., et al., Prognosis after ipsilateral breast tumor recurrence and locoregional recurrences in patients treated by breast-conserving therapy in five National Surgical Adjuvant Breast and Bowel Project protocols of node-negative breast cancer. J Clin Oncol, 2009. 27 (15): p. 2466–73. 4. Sanghani, M., et al., Predicting the Risk of Local Recurrence in Patients With Breast Cancer. American Journal of Clinical Oncology, 2007. 30 (5): p. 473–480. 5. Sanghani, M., et al., Validation of a Web-Based Predictive Nomogram for Ipsilateral Breast Tumor Recurrence After Breast Conserving Therapy. Journal of Clinical Oncology, 2010. 28 (5): p. 718–722. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-14-19.

Purpose: The purpose of this study is to determine the long-term significance of internal mammary lymph node (IMLN) detected by lymphoscintigraphy. Background IMLN metastasis is an important prognostic indicator in breast cancer. However, the necessity of internal mammary sentinel lymph node (IMSLN) biopsy for accurate staging, for choosing adjuvant treatment, and as a prognostic indicator, has remained controversial. Methods: From January 2001 until December 2006, 525 female breast cancer patients underwent radical surgery after preoperative lymphatic scintigraphy. We retrospectively analyzed the follow-up results, recurrences and deaths of all patients. Results: There was no significant difference in clinicopathologic characteristics between the axilla and the IMLN group. The median follow-up period was 118.8 (range, 7–122) months in the axilla group and 107.7 (range, 14–108) months in the IMLN group. During the median follow-up period, the breast cancer-related death rate in the axilla group was 3.6%, which was not significantly different from that of the IMLN group (1.3%) (P = 0.484). The five-year survival rates (5YRS) did not differ between the two groups (P = 0.306). The overall recurrence rate and the locoregional (LR) recurrence rate also did not differ between the two groups (P = 0.835 and P = 0.582, respectively. The recurrence rate of IMLN (both ipsilateral and contralateral) metastasis was very low, accounting for 0.5% in the axilla group and 1.3% in the IMLN group (P = 0.416). Conclusion: The long-term follow up results showed that there was no significant difference in both overall outcome and regional recurrence between the two groups. Therefore, the necessity of identification of nodal basins outside the axilla or the necessity of IMLN sentinel biopsy should be reconsidered. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-07-19.

Background: Breast cancer screening program makes it possible to detect early cancer, thus to reduce breast cancer mortality. The authors studied clinicopathologic characteristics and prognosis of screen detected invasive breast cancer compared with symptomatic breast cancer. Furthermore, we compared the result according to molecular subtypes (luminal A, luminal B, Her2, triple negative), so intended to identify the role of screening in each subtypes. Material and Methods: From January 2002 to June 2008, 3141 patients who underwent operation for the treatment of invasive ductal carcinoma(NOS) at Samsung medical center were included. Among them, 1025 patient were screen detected, 2116 patient were symptomatic, out of screening over 2 years. We reviewed the medical records retrospectively. Result: Screen detected breast cancer was associated with older patients, smaller tumor size, more hormone receptor- positive, less lymph node involvement, lower stage and reduced mortality compared with symptomatic breast cancer (P < .001). According to the molecular subtype, in luminal A subtype, the result shows better pathologic feature and also favorable overall and recur-free survial significantly. Conclusion: Compared to symptomatic breast cancer patients, screen detected breast cancer patients have favorable pathological and molecular characteristics, so better outcomes. According to the molecular subtype, only in luminal A subtype, screen detected breast cancer shows both overall and disease free survival benefit, and also acts as an independent prognostic factor itself. So, screening program seems to have a different efficacy depending on the molecular subtype of breast cancer Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-14-02.

Background: Metaplastic breeast cancer (MBC) is a rare, heterogenous cancer characterized by admixture of adenocarcinoma with metaplastic elements, low hormone receptor expression and poor outcome. This study was planned to assess the clinicopathological chacteristics and immunohistochemical findings of MBC compared to invasive ductal carcinoma (IDC) including the triple-negative subtype (TN-IDC). Material and Methods: We retrospectively reviewed the medical records of 47 MBC and 1,346 IDC patients. Two hundred eighteen TN-IDC patients were included in the 1,346 IDC patients. Between 2005 and 2009, these patients were undergone surgical treatment at the Samsung Medical Center. Patients were reviewed clinicopathologic factors, immunohistochemistry of biologic factors such as ER, PR, HER-2, p53, Ki67, cytokeratine (CK) 5/6, epidermal growth factor receptor (EGFR), and treatment modalities (type of operation, use of chemotherapy, radiotherapy and hormone therapy). Result: The MBC patients presented with a larger tumor size (>T1, 66.0% vs. 44.3.%, P = 0.008), lower lymph node involvement (N0, 73.3% vs. 55.6%, P = 0.03), higher histologic (HG) and nuclear grade (NG) (HG3, 70.0% vs. 41.5%, P = 0.001; NG3,82.6% vs. 46.9%, P < 0.001), fewer estrogen receptor (ER), progesterone receptor (PR) and HER2 positivity (ER+, 4.3% vs. 69.2%, P < 0.001; PR+, 6.4% vs. 63.5%, P < 0.001; HER2+, 0% vs. 27.6%, P < 0.001), higher p53, CK5/6 and EGFR expression (p53+, 63.8% vs.38.8%, P < 0.001; CK5/6+, 71.9% vs.21.5%, P < 0.001; EGFR+, 93.9% vs.21.6%, P Discussion: In our result, MBC show poorer clinical outcome than IDC. It is not shown significant difference between MBC and TN-IDC. However, MBC patients with nodal metastasis have poorer prognosis than TN-IDC patients with metastasis despite adjuvant chemotherapy. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-10-25.

Background: Differentiation by multigene signatures with excellent performance of hormone receptor (HR)-positive BC largely related to their proliferation genes. Despite questions about its usefulness, there is increasing evidence that Ki67 is a valuable prognostic marker. Standardization of Ki67 pathological assessment is the main problem to interpret reported trials. The aims of the study are to evaluate the role Ki67 as prognostic marker to predict relapse in HR-positive BC patients (luminal A and B) in adjuvant setting using prospective patients’ cohort. In addition, cut-off value and significant level of Ki67 were investigated comparing with other biomarkers including HER2 in luminal BCs. Method: We retrospectively analyzed the clinicopathologic characteristics of 1,070 postoperative breast cancer patients including Ki67 and clinical outcomes in terms of relapse free survival (RFS) between 2004 and 2007 at the Samsung Medical Center. Ki67 labelling index was measured in quantitative and semiquantitative method, independently. The percentage of positive nuclei stained for Ki67 was calculated each section based on the approximately 1,000 carcinoma cell nuclei. In addition, Ki67 was graded on a scale from 0 to 4, where 0 = staining of 0-4% of tumor cells, 1 = staining of 5-25% of tumor cells, 2 = 26-50% of tumor cells, 3 = staining of 51-75% of tumor cells, and 4 = staining of more than 76% of tumor cells. ROC curve was drawn to evaluate the usefulness of Ki67 index to get AUC then, find out the proper cut-off value of Ki67 to predict relapse. Multivariate analyses with Cox-regression model were performed. Results: Among 1,564 patients who received curative surgery for invasive breast cancer from January 2004 to June 2007, 1,070 patients with HR-positive were included in this analysis excluding 494 with HER2-enriched or triple negative breast cancer patients. Median follow-up duration was 56.9 months (range 36-77 months). Median age was 46 years (range 22-83 years). Ki67 threshold >19.5%, corresponding to a sensitivity 78.3%, a specificity 51.6% was chosen as cut-off value for relapse in adjuvant patients’ cohort. The AUC was 0.689 (P Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-06-01.

Background: Unlike western countries, median age of breast cancer is much younger and the proportion of young breast cancer (YBC) patients has been reported to be much higher in Korea. Considering YBC has usually worse clinical outcomes than older patients, long-term treatment complication, and higher prevalence premenopausal women, special consideration for more proper approach treating age merit. Although there are many conflicting results, there is still needs to define YBC, especially for each BC subtype. The purpose of our study was to investigate and determine clinicopathologic features and long-term outcome of YBC according to intrinsic subtype comprehensively. Methods: We retrospectively analyzed the presenting clinical and pathologic characteristic with intrinsic subtype using surrogate IHC (immunohistochemical) staining and treatment outcomes of 2,844 women who diagnosed with invasive breast cancer with age from 2000 to 2007 in Samsung Medical Center. We divided into three age groups as follows: ≤35 years (group 1), 35-50 years (group 2), and >50 years (group 3). In addition, intrinsic subtypes using IHC were divided into four groups as follows: Hormone receptor (HR)-+/HER2-; HER2+/HR-; HER2+/HR-; Triple Negative (TN). Results: During median follow-up duration of 100 months, 5-year recurrence free survival rate (RFSR) and overall survival rate (OSR) of all 2,884 patients were 90.8% and 94.6%, respectively. 10-year estimated RFSR and OSR were 81.9% and 86.9%, respectively. Median age was 46 years (range 21-83). Breast cancer patients aged with 40 or less comprised of 22% of all population in our cohort. Distribution of HR+ subtypes was different among three age groups (53.0% for group 1 vs. 65.1% for group 2 vs. 58.9% for group 3, p Conclusions: This analysis showed much high prevalence of YBC in this patients’ cohort. Poor outcomes of YBC patients might be from increased frequency of TN/HER2 subtypes and more aggressive clinical behavior of ER-positive tumors than in older patients. Clinical implications of age on tumor behavior were different according to subtypes. Further research to elucidate biologic difference of ER+ tumor in YBC patients is warranted. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-06-06.

Breast cancers (BC) in younger, premenopausal patients (YBC) tend to be more aggressive with worse prognosis, higher chance of relapse and poorer response to endocrine therapies compared to breast cancers in older patients. The proportion of YBC (age ≤ 40) among BC in East Asia is estimated to be 16-32%, significantly higher than the 7% reported in Western countries. In addition, approximately half of the Asian BC patients were premenopausal compared to 15-30% in the West. To characterize the molecular bases of Asian YBC, we have performed whole-exome sequencing (WES) and whole-transcriptome sequencing (WTS) on tumor and matched normal samples from 168 Korean BC patients consisting of 106 YBC cases (age ≤ 40) and 62 OBC cases (age > 40). We then performed comparison analyses with the TCGA BC cohort consisting of 1,116 tumors from primarily Caucasian patients, also grouped by age into YBC (age ≤ 40), IBC (40 < age ≤ 60) and OBC (age > 60). We performed logistic regression analyses to identify differentially expressed (DE) genes and pathways among age-based cohorts while controlling for the confounding effects of molecular subtype, tumor purity and stage. Within the Asian cohort, we found that estrogen response, endocrine therapy resistance, and various metabolism pathways are up-regulated in YBCs while cell cycle, proliferation and inflammatory pathways are up-regulated in OBCs. To separately examine molecular signatures from tumor, stroma and normal compartments, we used non-negative matrix factorization (NMF) analyses to virtually dissect bulk tumor expression data and identified 14 factors including 3 factors associated with normal tissues, 1 factor associated with stroma and 1 factor associated with tumor infiltrating leukocytes (TILs). By examining the correlation between pathway gene expression and NMF factors, we inferred that DE pathways such as fatty acid metabolism, bile acid biosynthesis, and epithelial-to-mesenchymal transition (EMT) were mainly active in stromal and normal tissue compartments. The TIL factor was significantly enriched in Asian BCs relative to Caucasian BCs with the highest TIL factor weight observed in Asian OBCs. Using gene expression signatures representing distinct types of TILs, we classified the combined cohort into three subtypes of varying TIL activities. Consistent with results from the NMF analysis, the TIL-high subtype is also significantly enriched in Asian BCs relative to Caucasian BCs. To our knowledge, this is the first large-scale multi-omics study of Asian breast cancer. Comparative analyses of multi-omics profiles from Asian and primarily Caucasian BC cohorts identified distinguishing molecular signatures associated with Asian BCs. Further, many signatures appeared to be specific to non-tumor compartments within bulk tumor, indicating that young Asian BCs may harbor distinctive tumor microenvironment. Citation Format: Yeon Hee Park, Ying Ding, Soo-Hyeon Lee, Hae Hyun Jung, Woosung Chung, Soonweng Cho, Jin-Ho Kim, Shibing Deng, Yoon-la Choi, Julio Fernandez, Se Kyung Lee, Seok Won Kim, Jeong Eon Lee, Ji-Yeon Kim, Jin Seok Ahn, Young-Hyuck Im, Seok Jin Nam, Woong-Yang Park, Zhengyan Kan. Comparative analyses of multi-omics profiles reveal distinctive molecular signatures of young Asian breast cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3370. doi:10.1158/1538-7445.AM2017-3370

Breast cancers (BC) in younger, premenopausal patients (YBC) tend to be more aggressive with worse prognosis, higher chance of relapse and poorer response to endocrine therapies compared to breast cancers in older patients (OBC). The proportion of YBC (age ? 40) among BC in East Asia is estimated to be 16-32%, significantly higher than the 7% reported in Western countries. Genomic and molecular characterizations have deepened our understanding of breast cancer biology in areas ranging from intrinsic subtypes to treatment responses, however, the molecular bases of Asian YBC remains poorly characterized. We have performed whole-exome sequencing (WES), whole-transcriptome sequencing (WTS) and high coverage targeted sequencing on tumor and matched normal samples from 133 Korean BC patients consisting of 74 YBC cases (age ? 40). We further performed immunohistochemistry (IHC) analyses to characterize tumor-infiltrating lymphocytes (TILs) in 46 tumors using four markers (CD45, CD4, CD8 and CD163). We found that BRCA1/2 germline deleterious mutations are enriched in YBC and the ER+/HER2- subtype, indicating that Asian ER+ YBC has a significant germline contribution. MutSig analysis4 identified ARID1A as a significantly mutated gene, implicating chromatin modeling as a cancer driver in Asian BC. Differential expression analyses suggested that Asian YBC differ in energy metabolism and are more active in protein synthesis than OBC tumors, whereas OBC is more proliferative than YBC. Using gene expression signatures representing distinct immune cell types and immunohistochemistry, we classified our cohort into four subtypes of varying TIL activities: high, medium, low and quiet. The majority of immunogenic cases with high TIL levels lie in ER+ or HER2+ subtypes although higher proportion is seen in TNBC. Moreover, YBC tumors appear to harbor lower levels of TIL activities than OBC, suggesting that younger patients may be less likely to benefit from immunomodulatory therapies than older patients. To our knowledge, this is the first large-scale multi-omics study of Asian breast cancer and would significantly contribute to the compendium of molecular data available for young, premenopausal breast cancer. While the major landmarks in the molecular and immune landscape of Asian BC look similar to that of the predominantly Caucasian BC cohorts, we have identified a number of distinguishing characteristics pointing to distinctive oncogenic mechanisms underlying Asian BC. Citation Format: Yeon Hee Park, Ying Ding, Soonweng Cho, Soo-Hyeon Lee, Hae Hyun Jung, Woosung Chung, Jinho Kim, Woong-Yang Park, Eric Powell, Pamela Vizcarra, Shibing Deng, Se Kyung Lee, Seok Won Kim, Jeong Eon Lee, Ji-Yeon Kim, Jin Seok Ahn, Young-Hyuck Im, Seok Jin Nam, Zhengyan Kan. Multi-omics and immuno-oncology profiling of an Asian breast cancer cohort enriched in young and premenopausal patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-325.

Background: Near-infrared (NIR) fluorescence-guided sentinel lymph node biopsy (SLNB) using indocyanine green (ICG) has been successfully applied in various kinds of cancers, especially in breast cancer. Optimizing the concentration of ICG without using human serum albumin in natural lymphatic system is still required. Methods: 25mg of ICG was diluted with distilled water (DW) or normal saline (NS). Dilution concentrations used for measurement were 0.25μg/mL, 0.5μg/mL, 2.5μg/mL, 5.0μg/mL, 25μg/mL, and 250μg/mL. The brightness of fluorescence was measured by an image system called Visual Navigator (SH System, Korea). We used graphic software (GIMP, version 2.8.14, The GIMP Team) to measure the brightness. We assumed that drained serous lymphatics from a breast cancer patient can reflect a natural lymphatic condition injected with ICG in the operation field. Drained lymphatics were mixed to reduce the concentration of ICG by half that was diluted with DW or NS. We also measured the brightness of fluorescence diluted with DW or NS that was mixed with drained lymphatics. After this screening test, we subdivided the range which brightness was measured as 100 and adjusted the intensity of illumination for more specific results. Results: Highest brightness values were measured as 100 between 2.5μg/mL and 25μg/mL concentration of ICG with DW dilution in screening settings, and the values of brightness were measured as 100 between 2.5μg/mL and 5.0μg/mL concentration of ICG with NS dilution. When drained lymphatics were mixed together, the values of brightness were measured as 100 between 2.5μg/mL and 25μg/mL concentration of ICG with DW or NS dilution. After subdividing the ICG concentration to 2.5μg/mL, 3.13μg/mL, 5.0μg/mL, 6.25μg/mL, 12.5μg/mL and 25μg/mL with adjusting the intensity of illumination, the highest brightness value was measured as 76 in 5.0μg/mL concentration of ICG with DW dilution. When diluting with NS, the highest brightness value was measured as 61 in 5.0μg/mL ICG concentration. After mixing with drained lymphatics, the highest brightness value was both 79 in 5.0μg/mL concentration of ICG with DW and NS dilution. Conclusions: This study showed a practically optimal ICG concentration range in fluorescence guided SLNB. The optimal range of ICG concentration is from 3.13μg/mL to 6.25μg/mL with DW or NS dilution. Although 5.0μg/mL met the best result, adjustment for individual settings may be considered. Citation Format: Paik H-J, Yi HW, Park S, Ryu JM, Nam SJ, Lee JE, Kil WH, Lee SK, Bae SY, Kim SW. Optimal concentration of indocyanine green in near-infrared fluorescence guided sentinel lymph node biopsy in breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-01-03.

Background The purpose of this study was to identify the feasibility and accuracy of sentinel lymph node biopsy (SLNB) after neoadjuvant chemotherapy (NAC) in patients with axillary lymph node (ALN) metastasis at diagnosis. Methods This is a retrospective study of 332 patients who were diagnosed with invasive breast cancer and ALN metastasis and treated with NAC followed by curative surgery at Samsung Medical Center between January 2007 and December 2013. Patients were classified into five groups according to surgical procedure for the ALNs and pathologic results; group 1, patients with negative SLN status and no further dissection was performed; group 2, patients with negative SLN status undergoing further axillary lymph node dissection (ALND); group 3, patients with positive or undetected SLNs undergoing further ALND; group 4, patients without residual axillary metastasis undergoing complete ALND; and group 5, patients with pathologic nodal positive disease undergoing ALND. Results Sentinel lymph nodes identification rate after NAC was 99.1% and false negative rate was 24.1%. The median number of retrieved SLNs was 4 (range, 1–10). There was no difference in the overall survival among the groups (p=0.06). There was no significant difference in the disease-free survival rate between the SLNB only and complete ALN dissection groups who revealed a pathologic complete node response (79.6% versus 80.5%) and the rate of axillary recurrence demonstrated no significant differences among the groups. (p=0.225) There was a statistical difference of recurrence between group 1 versus 2, and group 1 versus 4 in hormone receptor-negative patients. (p=0.027) Conclusion SLNB after NAC in breast cancer patients with initial ALN metastasis may help identify downstaging to negative nodal status and thereby reduce the surgical morbidity by avoiding standard ALN dissection. Citation Format: Park S, Ryu JM, Paik H-J, Yi HW, Bae SY, Lee SK, Kil WH, Kim SW, Lee JE, Nam SJ. Sentinel lymph node biopsy alone after neoadjuvant chemotherapy in patients with cytologically proven node-positive breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-01-08.

Epithelial-mesenchymal transition (EMT), a switch of polarized epithelial cells to a migratory, fibroblastoid phenotype, is considered a key process driving tumor cell invasiveness and metastasis. Using breast cancer cell lines as a model system, we sought to discover gene expression signatures of EMT with clinical and mechanistic relevance. A supervised comparison of epithelial and mesenchymal breast cancer lines defined a 200-gene EMT signature that was prognostic across multiple breast cancer cohorts. The immunostaining of LYN, a top-ranked EMT signature gene and Src-family tyrosine kinase, was associated with significantly shorter overall survival (P = 0.02) and correlated with the basal-like (“triple-negative”) phenotype. In mesenchymal breast cancer lines, RNAi-mediated knockdown of LYN inhibited cell migration and invasion, but not proliferation. Dasatinib, a dual-specificity tyrosine kinase inhibitor, also blocked invasion (but not proliferation) at nanomolar concentrations that inhibit LYN kinase activity, suggesting that LYN is a likely target and that invasion is a relevant end point for dasatinib therapy. Our findings define a prognostically relevant EMT signature in breast cancer and identify LYN as a mediator of invasion and a possible new therapeutic target (and theranostic marker for dasatinib response), with particular relevance to clinically aggressive basal-like breast cancer. Cancer Res; 70(6); 2296–306

Background It has been widely accepted that small and node-negative breast cancers have an excellent prognosis and do not generally have clinical benefit from adjuvant chemotherapy. Recently, the role of adjuvant chemotherapy for small node negative breast cancers has been justified in some high-risk patients, which include HER2−positive and triple negative breast cancers. However, the question has been raised as to whether there are some patients who might have benefit from adjuvant chemotherapy in small node-negative HR-positive breast cancers. According to the current 2011 NCCN guideline, 21-gene RT-PCR assay can be considered for tumor size of more than 0.5 cm in HR-positive, HER2−negative cancers. In cases of high recurrence score (≥ 31), adjuvant chemotherapy in addition to endocrine therapy is recommended as category 2B. Because gene array cannot routinely be used in clinical practice and has not been validated in prospective randomized trials and the usefulness of it still needs to be defined, it would be better if there were valuable markers to determine risk for relapse in this setting. We hypothesized that there could be a population who might have clinical benefit from adjuvant chemotherapy in this small node-negative HR-positive tumors. Patients and Methods We retrospectively analyzed the clinicopathologic characteristics and outcomes of 538 postoperative HR-positive (ER-positive and/or PgR-positive) T1b-cN0 breast cancer patients between 2004 and 2007 at the Samsung Medical Center. We performed Cox regression multivariate analysis for relapse using variables from univariate analysis by log-rank test for relapse. Results: The median age at diagnosis was 46 years (range, 22–79). During the median 60.5 months of follow-up, the 5-year recurrence rate was 5.2%. Anthracycline-based adjuvant chemotherapy was administered to 44.8% of the patients. Adjuvant endocrine and radiation treatment were administered to 94.6% and 63.7% of the patients. There were significant differences according to histologic grade (HG), Ki67 index, and age of less than 35 years in univariate analyses regarding RFS (p=0.003, p Conclusion: A patients’ population may exist who have clinical benefit from adjuvant chemotherapy in T1b-cN0 HR-positive breast cancer patients. Ki67 index and age are useful as valuable surrogate markers to predict recurrence and to have benefit from adjuvant chemotherapy in this population. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-01-11.

Large body of evidence suggests that obesity is associated with poor survival of breast cancer. However, this association is not entirely consistent among younger or premenopausal women. We investigated the association of obesity and the survival from pre- and postmenopausal breast cancer in Korea. Breast cancer patients in this study were women who previously participated in a hospital-based case-control study. A total of 1,357 patients (937 premenopausal and 420 postmenopausal women) who were first diagnosed between 1998 and 2004 and aged between 35 and 70 were included in the study. Patients were interviewed at the time of diagnosis on the risk factors of breast cancer including current body weight, weight at 2 years prior to diagnosis, weight at age 18, and adult height. Clinical records and pathologic reports were retrieved and the information on tumor characteristics, such as TNM, stage, estrogen receptor (ER), progesterone receptor (PR), and C-erbB-2, and type of treatment were coded. Patients were followed up until Dec. 31, 2007. Deaths were confirmed through hospital cancer registry and the National Death Certificate Database. Hazard ratios (HR) were calculated using Cox's proportional hazard model. We observed 111 deaths from all cause and 74 deaths from breast cancer. Five-year survival rate for breast cancer was 94.4% for premenopausal patients and 96.2% for postmenopausal patients. Obesity was not associated with breast cancer mortality in premenopausal patients. Compared to women with Body Mass Index (BMI) at diagnosis < 25kg/m2, women with BMI >= 25kg/m2 had 0.7 times risk of death from breast cancer (95% Confidence Interval (CI) = 0.3-1.4). However, obesity was positively associated with breast cancer mortality in postmenopausal patients. Compared to women with BMI at diagnosis < 25kg/m2, women with BMI >= 25kg/m2 had 3.1 times higher risk of death from breast cancer (95% CI = 1.1-8.7). Weight loss during the two years prior to diagnosis was associated with breast cancer mortality in premenopausal patients. Compared to women whose weight changed less than 5 % during the 2 years prior to diagnosis, women who lost more than 5% of their weight had 2.9 times higher risk of death from breast cancer (95% CI = 1.4-6.1). Women who gained more than 5% of their weight did not have increased risk of death from breast cancer (HR = 1.2, 95% CI = 0.6-2.2). There was no association between weight change and breast cancer mortality in postmenopausal patients (HR for weight loss group = 0.9, 95% CI = 0.2-3.8, HR for weight gain group = 0.9, 95% CI = 0.2-4.0). In conclusion, obesity was associated with poorer survival of breast cancer in postmenopausal women but not in premenopausal women. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 893.