Search

Despite recent advances in chemotherapy, the prognosis for patients with advanced gastric cancer (GC) or gastroesophageal junction cancer remains poor. Human epidermal growth factor receptor 2 (HER2) is a novel target for biologic therapy in metastatic GC. We analyzed the association between HER2 overexpression and the clinicopathologic characteristics of advanced GC. Formalin-fixed, paraffin-embedded tumor samples were collected from patients with stage III or to IV (M(0)) GC who subsequently underwent curative surgery followed by adjuvant chemotherapy with 5-fluorouracil and cisplatin. All the samples were analyzed for HER2 status by immunohistochemistry (IHC) and fluorescence in situ hybridization. Of 142 samples analyzed, 7.1% scored IHC 2+ and 8.6% scored IHC 3+, whereas 9.3% were HER2-amplified. Of HER2-amplified cases, 76.9% (10/13) scored IHC 3+, showing the correlation between HER2 amplification and overexpression (P=0.01). HER2 IHC 3+ cases were more common in the intestinal-type tumors compared with diffuse-type tumors (16.7% vs. 5.1%, respectively; P=0.049), and a nonsignificant trend was observed using fluorescence in situ hybridization (14.3% vs. 9.2%, respectively; P=0.399). HER2 gene amplification was more frequent in stage IV (M(0)) than stage III disease (15.4% vs. 4.0%, respectively; P=0.037). Interestingly, HER2-amplified disease was more common than nonamplified disease in patients with nodal stage 3 tumors (76.9% vs. 38.6%, respectively; P=0.009); a similar pattern was observed using IHC. HER2 overexpression correlated with nodal stage, and a lymph node ratio greater than 0.5 was more common in HER2-amplified tumors than HER2-nonamplified tumors (69.2% vs. 43.3%, respectively; P=0.086). These findings suggest that further investigations of adjuvant therapy with HER2-targeted therapy for advanced GC are warranted.

Background Gastric hepatoid adenocarcinoma (HAC) is a special type of gastric cancer that morphologically mimics hepatocellular carcinoma. In this study, we performed an evaluation of clinicopathologic characteristics, treatment outcome, and prognosis in patients with gastric HAC. Methods We consecutively enrolled patients with pathologically proven gastric HAC at Seoul National University Hospital between January 1996 and December 2008 and conducted a retrospective review. Among 15,253 patients with gastric cancer, 26 patients (0.17%) were diagnosed as gastric HAC. Results Among 26 patients, 22 were male and the median age was 63. Stage at diagnosis was stage IB in 3 patients, stage II in 6 patients, stage III in 7 patients, and stage IV in 10 patients. Eight patients out of 18 patients with stage IB, II, III, and IV relapsed after curative surgery. Relapse-free survival for these patients was 16.67 months. The most common metastatic site was intraabdominal lymph nodes (n = 9), followed by the liver (n = 8). Thirteen patients received palliative chemotherapy. The most commonly used regimen was a combination of fluoropyrimidine and platinum. Partial response was observed in one patient and stable disease in 5 patients. Median overall survival and progression free survival of these patients were 8.03 (95% CI: 6.59-9.47) and 3.47 months (95% CI: 0.65-6.29), respectively. Conclusions Gastric HAC is a very rare but unique type of stomach cancer. Early detection of this type of cancer is of critical importance to patient prognosis. Additional studies to reveal the biology of this tumor are warranted.

Introduction Triple negative breast cancer (TNBC) has a poorer survival, despite a higher response rate to neoadjuvant chemotherapy. The purpose of this study was to identify the predictive or prognostic value of Ki-67 among patients with TNBC treated with neoadjuvant chemotherapy, and the role of Ki-67 in further classification of TNBC. Methods A total of 105 TNBC patients who received neoadjuvant docetaxel/doxorubicin chemotherapy were included in the present study. Pathologic complete response (pCR) rate, relapse-free survival (RFS), and overall survival (OS) were compared according to the level of Ki-67. Results pCR was observed in 13.3% of patients. TNBC with high Ki-67 expression (≥10%) showed a higher pCR rate to neoadjuvant chemotherapy than TNBC with low Ki-67 expression. None of the low Ki-67 group achieved pCR (18.2% in the high Ki-67 group vs. 0.0% in the low Ki-67 group, P = 0.019). However, a high Ki-67 expression was significantly associated with poor RFS and OS in TNBC, despite a higher pCR rate (P = 0.005, P = 0.019, respectively). In multivariate analysis, high Ki-67 was an independent prognostic factor for RFS in TNBC (hazard ratio = 7.82, P = 0.002). The high Ki-67 group showed a similar pattern of recurrence with overall TNBC, whereas the low Ki-67 group demonstrated a relatively constant hazard rate for relapse. Conclusions TNBC with high Ki-67 was associated with a more aggressive clinical feature despite a higher pCR rate. High proliferation index Ki-67 can be used for further classification of TNBC into two subtypes with different responses and prognosis.

To analyze the outcome of adjuvant chemoradiotherapy for patients with extrahepatic bile duct (EHBD) cancer, and to identify the prognostic factors for these patients.Between January 1995 and December 2002, 86 patients with adenocarcinoma of EHBD underwent curative resection followed by adjuvant chemoradiotherapy. There were 59 male and 27 female patients, and median age was 59 years (range, 34 to 73 y). Postoperative radiotherapy was delivered to tumor bed and regional lymph nodes up to 40 Gy at 2 Gy/fraction with a 2-week planned rest. Intravenous 5-fluorouracil (500 mg/m(2)/d) was given on day 1 to 3 of each split course. The median follow-up period was 83 months for survivors.Forty-eight patients failed the treatment: locoregional recurrence in 20, distant metastasis in 38, and both locoregional and distant relapses in 10 patients. Five-year locoregional relapse-free survival rate was 70.3%. On multivariate analysis, resection margin status was the only significant prognosticator (P=0.0299). Five-year distant metastasis-free survival rate was 53.6%. Three or more involved lymph nodes had an adverse impact on distant metastasis-free survival (P=0.0334). Five-year overall survival rate was 44.7%, and poorly differentiated tumor was associated with inferior overall survival (P=0.0297).Adjuvant chemoradiotherapy after curative resection can achieve a long-term survival in patients with EHBD cancer. Resection margin status, number of involved lymph nodes, and histologic differentiation are associated with locoregional relapse, distant metastasis, and overall survival, respectively. Distant metastasis was the major pattern of failure, possibly due to the increased locoregional control by use of adjuvant chemoradiotherapy. Intensification of systemic treatment is warranted.

Central nerve system (CNS) metastases are a feared complication of breast cancer and are associated with poor prognosis. The purpose of this study is to investigate the clinical characteristics of CNS metastases and to clarify the prognostic factors after CNS metastases in breast cancer at a single institution over a long time period. We retrospectively reviewed the medical records of breast cancer patients diagnosed at Seoul National University Hospital from 1981 to 2009 and identified the patients who experienced CNS metastases. We collected the data, including demographics, clinico-pathologic characteristics, dates of diagnosis of original breast cancer and subsequent metastases, and date of death, and correlated the findings with the clinical outcome. A total of 400 patients were identified, of whom 17 (4.3%) were diagnosed with CNS metastases and primary breast cancer concurrently and 383 (95.7%) experienced CNS metastases subsequent to the diagnosis of primary breast cancer. Further, 318 patients (79.5%) had only brain parenchymal metastases, 30 (7.5%) had only leptomeningeal metastases, and 52 (13%) had both. After the diagnosis of CNS metastasis, 170 patients (42.5%) received systemic chemotherapy (CTx) and 143 (35.8%) received CTx after whole brain radiation therapy (WBRT). The patients with good performance status (PS), initial CNS metastasis as recurrence, absence of extracranial metastases, non-visceral extracranial metastases, longer interval from the date of primary breast cancer to the date of CNS metastasis, and CTx after WBRT and gamma-knife surgery (GKS), had better outcomes in univariate analyses. In multivariate analysis, good PS, systemic CTx after WBRT, GKS, and longer interval to CNS metastasis, were independent prognostic factors for overall survival after CNS metastases. Our results suggest that appropriate palliative systemic therapy after WBRT or GKS, and adequate palliative treatment via combined modalities are helpful for breast cancer patients, even after the detection of CNS metastases.

The study aims to determine whether or not oral mucositis (OM) during active chemotherapy in patients with solid tumors is representative of the patient’s quality of life (QOL) and the suffering from adverse effects. From October 2007 to September 2008, we prospectively enrolled 344 consecutive patients with solid tumors who initiated a new chemotherapy regimen. OM, other adverse effects, and the QOL were surveyed by face-to-face interviews and patient diaries. OM developed during 175 of 633 cycles (27.7%). Forty-five percent of the patients experienced OM during two cycles of chemotherapy. The QOL in patients with OM was significantly lower than patients without OM, as evaluated by the Functional Assessment of Cancer Therapy—General (70.26 ± 15.36 and 75.09 ± 13.12, respectively; p

The aim of this study was to determine the expression of molecular markers in metastatic colorectal cancer (mCRC) and the concordance between primary tumor and metastasis. We also aimed to determine the relationship between molecular markers and clinical outcomes of cetuximab-containing chemotherapy.Seventy-five mCRC patients who received cetuximab-containing chemotherapy between 2000 and 2008 were consecutively enrolled. EGFR, p-EGFR, PTEN, and IGF-1R expression by immunohistochemistry, DNA sequencing for EGFR, KRAS, BRAF, and PI3 KCA, and EGFR amplification by FISH were done.The positive expression of EGFR, p-EGFR, PTEN, and IGF-1R was determined in 45 (64.3%), 9 (14.8%), 35 (50.7%), and 10 patients (16.1%), respectively. EGFR gene amplification or high polysomy was detected in 10 patients (17.6%). KRAS mutation and BRAF mutation were detected in 19 patients (27.5%) and five patients (7.0%), respectively. Among tested biomarkers, only the EGFR intron 1 CA repeat polymorphism and BRAF mutation showed concordance (kappa = 0.600, P = 0.003; and kappa = 0.692, P = 0.001, respectively) between primary tumor and paired metastasis. Skin rash was a strong predictive marker for response rate, PFS, and OS. In KRAS mutant tumors, PTEN expression was associated with a longer PFS. BRAF mutation was related to poor outcome in KRAS wild-type tumors.BRAF mutations and EGFR intron 1 CA repeat polymorphisms were concordant between primary tumors and paired metastases. In KRAS mutant tumors, PTEN expression was a predictive marker for favorable outcomes. In KRAS wild type, BRAF mutation was strong predictive markers for poor outcomes.

Trastuzumab, a HER2 directed treatment has shown clinical benefit in HER2 amplified gastric cancer. This study demonstrated the potent antitumor activity of HM781-36B, a quinazoline-based irreversible pan-HER inhibitor, in HER2 amplified gastric cancer cells (SNU216 and N87) in vitro and in vivo. HM781-36B inhibited phosphorylation of HER family and downstream signaling molecules, and induced apoptosis and G1 arrest. Furthermore, HM781-36B exerted synergistic effects with chemotherapeutic agents in both HER2 amplified and HER2 non-amplified gastric cancer cells. Therefore, HM781-36B may be useful for the treatment of HER2 amplified gastric cancer alone or in combination with chemotherapeutic agents.

Little is known about the benefits of preoperative staging chest computed tomography (CT) in patients with asymptomatic breast cancer. We therefore investigated the clinical value of preoperative chest CT in detecting lung and liver metastases by retrospectively reviewing the records of 1,703 patients who underwent preoperative chest CT in a single institution between January 2006 and June 2009. Abnormal CT findings, including suspected metastases and indeterminate nodules in the lung or liver, were found in 266 patients (15.6%). Among these, 26 patients (1.5% of all patients and 9.8% of patients with abnormal CT findings) had true metastases, including 17 in the lungs, 3 in the liver, and 6 in both. True metastases were detected in 1 (0.2%), 0 (0%), and 24 (6.0%) patients with stage I, II, and III disease, respectively. The sensitivity, specificity, and positive predictive value of chest CT were 100, 89.1, and 11.3%, respectively, for lung metastasis and 100, 97.6, and 18.4%, respectively, for liver metastasis. All true metastatic lung lesions were all small-sized nodules, ranging from 0.2 to 1.5 cm in largest diameter, and could not be detected on chest X-rays. In conclusion, our results demonstrate the lack of usefulness of routine preoperative chest CT in detecting asymptomatic liver and lung metastasis in patients with early breast cancer. Chest CT, however, upstaged 6.0% of stage III patients to stage IV.

DNA methyltransferase (DNMT) 1 and 3 are primarily responsible for abnormal methylation in cancer. Unlike these DNMTs, DNA methyltransferase 3-like (DNMT3L) harbors no conserved catalytic domain, and has been shown to function as a regulatory cofactor for DNA methylation. However, it is unclear whether DNMT3L directly regulates DNA methylation in cancer cells. To address this, we investigated the methylation targets of DNMT3L by conducting methylation microarray trials after the siRNA-induced knockdown. We determined that methylation of 242 out of 1,505 CpG sites was significantly altered by DNMT3L knockdown. Among these 242 CpG sites, 204, 12, and 11 CpG sites were identified as common targets of DNMT 1/3B/3L, 1/3L, and 3B/3L, respectively; this indicates that DNMT3L participates in DNA methylation via cooperation with other DNMTs. However, we also determined that the methylation of 15 CpG sites was significantly altered by DNMT3L knockdown only. As a validation, we confirmed that thymine DNA glycosylase (TDG), an enzyme involved in the base excision repair of mismatched-DNA, was up-regulated in DNMT3L knockdown cells, but neither in DNMT1 nor 3B knockdown cells. Methylation-specific PCR (MSP) also showed that promoter methylation of TDG was decreased in DNMT3L knockdown cells. Interestingly, 5-aza-2'-deoxycitidine (5-aza-dC) re-expressed DNMT3L, leading to down-regulation of TDG. This study is the first to show that DNMT3L exerts a major effect on the transcriptional regulation of a specific target gene, such as TDG, despite the absence of enzymatic activity.

Lapatinib and capecitabine combination therapy is effective in trastuzumab-resistant human epidermal growth factor receptor 2 (HER2)-positive breast cancer. We investigated the biomarkers from serum of patients receiving lapatinib and capecitabine Patients received lapatinib 1,250 mg once daily and capecitabine 2,000 mg/m(2)/day, day 1-14, every 3 weeks. Serum samples were obtained before treatment initiation. Levels of transforming growth factor-α (TGF-α), epidermal growth factor (EGF), extracellular domains of EGFR and HER2 were measured by enzyme-linked immunosorbent assay. The effect of TGF-α on in vitro sensitivity of SK-BR-3 cells to lapatinib was investigated. Sixty-four patients were included. Response rate was significantly higher in patients with low serum TGF-α (≤ 3.75 pg/ml) compared to high TGF-α (3.75 pg/ml) [61.1% (11/18) vs. 17.4% (8/46), respectively; P = 0.001]. Low serum TGF-α was independently associated with better response in multivariate analysis [adjusted odds ratio, 8.96; 95% confidence interval (CI) 2.4-34.2]. Time-to-progression tended to be shorter in patients with high serum TGF-α compared to low TGF-α [median 3.8 months (95% CI 2.3-5.4) vs. 6.5 (95% CI 6.1-6.8), respectively; P = 0.067]. We confirmed that TGF-α diminished the sensitivity of SK-BR3-cells to lapatinib in vitro. The in vitro antiproliferative effect of cetuximab in combination with lapatinib was higher than that of lapatinib alone in SK-BR3-cells exposed to TGF-α. These data suggest that TGF-α plays a role in resistance to lapatinib and capecitabine therapy among HER2-positive breast cancer.

KRAS is frequently mutated in nonsmall cell lung cancer (NSCLC), resulting in the activation of the MAPK/ERK kinase (MEK)/ERK pathway. High-throughput mutation profile has shown that lung cancer frequently harbors comutation of cancer-related genes. Therefore, given that cancer cells have multiple genetic alterations, combinatorial therapeutic strategy is demanded for effective cancer therapy. To address this, we first characterized MEK dependence in four NSCLC cells. Two cells (H358, A549) carried KRAS mutation only, and the other two (H23, H157) harbored comutation of KRAS/PTEN. H358 cells with KRAS mutation only were sensitive to MEK inhibition. However, the other KRAS mutant A549 cells were resistant to MEK inhibition. Previously, we have shown that dual inhibition of EGFR and MEK signaling shows a synergistic effect on KRAS mutant gastric cancer cells by suppressing compensatory activation of AKT. Here we also observed that this combination was effective in KRAS mutant A549 cells. However, the combination was ineffective in H23 and 157 cells with comutation of KRAS/PTEN. Compared to KRAS mutant/PTEN wild-type cells, signal transducer and activator of transcription 3 (STAT3) was significantly activated following MEK inhibition in KRAS/PTEN comutant cells. Combined STAT3 inhibition by a JAK2 inhibitor or gene knockdown with MEK inhibition blocked STAT3 activation, synergistically suppressed cell growth, and induced apoptosis in comutant cells. Taken together, our study provides molecular insights that help explain the heterogeneous response to MEK inhibition in KRAS mutant lung cancers, and presents a rationale for the clinical investigation of combination of MEK and EGFR inhibitor or MEK and JAK2 inhibitor depending on PTEN status.

We evaluated RAD001, an inhibitor of the mammalian target of rapamycin (mTOR) in human gastric cancer cell lines and determined the molecular mechanisms. RAD001 has marked growth inhibitory activity against the SNU-1 and SNU-216 cells. It inhibited phosphorylation of mTOR and S6 K, and induced G1 cell cycle arrest. Synergistic growth-inhibitory effects in combination with 5-fluorouracil (5-FU) was identified. Furthermore, RAD001 conferred sensitivity to 5-FU-resistant cell lines by downregulating thymidylate synthase (TS). In conclusion, RAD001 showed growth inhibitory activity against gastric cancer cells and acted synergistically with cytotoxic agents such as 5-FU by downregulating TS.

Background Triple-negative (TN) breast cancer, which is defined as being negative for the estrogen receptor (ER), the progesterone receptor (PR), and the human epidermal growth factor receptor 2 (HER-2), represents a subset of breast cancer with different biologic behaviour. We investigated the clinicopathologic characteristics and prognostic indicators of lymph node-negative TN breast cancer. Methods Medical records were reviewed from patients with node-negative breast cancer who underwent curative surgery at Seoul National University Hospital between Jan. 2000 and Jun. 2003. Clinicopathologic variables and clinical outcomes were evaluated. Results Among 683 patients included, 136 had TN breast cancer and 529 had non-TN breast cancer. TN breast cancer correlated with younger age (< 35 y, p = 0.003), and higher histologic and nuclear grade (p < 0.001). It also correlated with a molecular profile associated with biological aggressiveness: negative for bcl-2 expression (p < 0.001), positive for the epidermal growth factor receptor (p = 0.003), and a high level of p53 (p < 0.001) and Ki67 expression (p < 0.00). The relapse rates during the follow-up period (median, 56.8 months) were 14.7% for TN breast cancer and 6.6% for non-TN breast cancer (p = 0.004). Relapse free survival (RFS) was significantly shorter among patients with TN breast cancer compared with those with non-TN breast cancer (4-year RFS rate 85.5% vs. 94.2%, respectively; p = 0.001). On multivariate analysis, young age, close resection margin, and triple-negativity were independent predictors of shorter RFS. Conclusion TN breast cancer had higher relapse rate and more aggressive clinicopathologic characteristics than non-TN in node-negative breast cancer. Thus, TN breast cancer should be integrated into the risk factor analysis for node-negative breast cancer.

The purpose of this study was to demonstrate the beneficial effect of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in the treatment of leptomeningeal metastasis (LM) for a select group of non-small cell lung cancer (NSCLC) patients who had a sensitive EGFR mutation or good predictive clinical factors for EGFR TKI treatment. Eleven patients with NSCLC and LM were treated with a standard dose of erlotinib (n = 9), or higher than standard dose of gefitinib followed by erlotinib (n = 2). They were treated with various therapies including whole brain radiotherapy or intrathecal chemotherapy for CNS lesion previously and concurrently with EGFR TKI. Nine of 11 patients showed overt improvement in ECOG performance status. Six patients were alive >6 months, and 2 additional patients were alive 2.5+ and 4.4+ months with clinical improvement. Two patients showed responses to higher than standard dose of gefitinib. The median overall survival was not reached. In conclusion, EGFR TKIs are effective in the treatment of LM from NSCLC when patients were selected properly.

We describe a 37-yr-old man who developed central pontine myelinolysis (CPM) after allogeneic hematopoietic stem cell transplantation (HSCT) for acute lymphoblastic leukemia. After HSCT, desquamation developed on the whole body accompanied by hyperbilirubinemia. The liver biopsy of the patient indicated graft-versus-host disease- related liver disease, and the dose of methylprednisolone was increased. Then, the patient developed altered mentality with eye ball deviation to the left, for which electroencephalogram and magnetic resonance imaging (MRI) scans were done. Brain MRI scan demonstrated the imaging findings consistent with central pontine myelinolysis and extrapontine myelinolysis. He did not have any hyponatremia episode during hospitalization prior to the MRI scan. To the best of our knowledge, presentation of CPM after allogeneic HSCT is extremely rare in cases where patients have not exhibited any episodes of significant hyponatremia. We report a rare case in which hepatic dysfunction due to graft-versus-host disease has a strong association with CPM after HSCT.

Although non-small cell lung cancer (NSCLC) cells with somatic mutations in their epidermal growth factor receptors (EGFR) initially show a dramatic response to tyrosine kinase inhibitor (TKI), these cells eventually develop resistance to TKI. This resistance may be caused by a secondary T790M mutation in the EGFR tyrosine kinase, which leads to the substitution of methionine for threonine in 790. In this study, we show that a combination of lapatinib and cetuximab overcomes gefitinib resistance in NSCLC with the T790M mutation. We observed that T790M lung cancer cells were resistant to gefitinib, and Stat3 was persistently activated in the resistant cells. A reversible EGFR and HER2 TKI, lapatinib, decreased Stat3 activation by blocking heterodimerization of EGFR and HER2, which led to a modest increase in the inhibitory effect on gefitinib-resistant T790M cells. In addition to lapatinib, the anti-EGFR antibody, cetuximab, induced down-regulation of EGFR and apoptotic cell death in T790M cells. Finally, combined lapatinib and cetuximab treatment resulted in significantly enhanced cytotoxicity against gefitinib-resistant T790M cells in vitro and in vivo. Taken together, these data suggest that treatment with a combination of lapatinib and cetuximab, which induces dimeric dissociation and EGFR down-regulation, appears to be an effective strategy for treatment of patients with EGFR TKI-resistant NSCLC. [Mol Cancer Ther 2008;7(3):607–15]

Background Ampulla of Vater cancer (AoV Ca) is a rare tumor, and its adjuvant treatment has not been established. The purpose of this study was to find out prognostic factors including host immunity and role of adjuvant treatment in AoV Ca. Methods and Findings We reviewed 227 AoV Ca patients with curative resection. Clinical characteristics, adjuvant treatment, disease-free survival (DFS) and overall survival (OS) were analyzed. Among all patients, 63.9, 36.1 and 33.9% had T1/T2, T3/T4 stage and lymph node-positive disease (LN+), respectively. OS of all patients was 90.9 months (95% CI: 52.9–129.0). OS was different according to neutrophil-to-lymphocyte ratio (HR 1.651, 95% CI: 1.11–2.47), platelet-to-lymphocyte ratio (HR 1.488, 95% CI: 1.00–2.21) and systemic inflammatory index (HR 1.669, 95% CI: 1.13–2.47). In multivariate analysis, adverse prognostic factors for OS included vascular invasion (HR 2.571, 95% CI: 1.20–5.53) and elevated CA 19–9 (HR 1.794, 95% CI: 1.07–3.05). A total of 104 patients (46.3%) received adjuvant treatment (25 out of 111of T1/T2 & LN (-), 79 out of 116 of T3/T4 or LN (+)). In T3/T4 or LN (+) stage, adjuvant CCRT with maintenance chemotherapy provided the longest OS (5-year OS rate: 47.0 vs. 41.4%). Conclusions Vascular invasion and elevated CA 19–9 were adverse prognostic factors in resected AoV Ca. In T3/T4 or LN (+) stage, adjuvant CCRT with maintenance chemotherapy provided the best survival outcome. Adjuvant treatment should be further defined in AoV Ca, especially with poor prognostic factors.

56 Background: Anti-angiogenic strategy in gastric cancer (GC) has been highlighted again due to the recent success of ramucirumab and apatinib. Therefore, the comprehensive network of VEGF, soluble VEGF receptor-2 (sVEGFR2) and cytokines and other angiogenic factors (CAF) in GC and their prognostic impact would be of importance, although they have been poorly understood. We aimed to find out the CAF signature associated with VEGF and sVEGFR2, and to explore their prognostic implication in GC. Methods: We measured pretreatment serum levels of 52 CAFs, including VEGF and sVEGFR2, using multiplex bead immunoassays and ELISA, in 70 patients who were diagnosed with GC in Seoul National University Hospital, and treated with palliative chemotherapy. Linear regression analysis for correlating CAFs with VEGF and sVEGFR2, and survival analysis by log rank test and Cox regression analysis were performed. Results: The VEGF signature was shown to be associated with seven CAFs (interluekin [IL]-7, IL-12p70, IL-2Ra, IL-10, stem cell factor, Fibroblast growth factor-basic, IL-3). The sVEGFR2 signature was associated with IL-4 and platelet-derived growth factor beta, but VEGF and sVEGFR2 showed no association with each other. Patients with high VEGF had a tendency to have worse overall survival (OS) than those with low VEGF (11.2 months versus 16.7 months; P = 0.061). However, among patients with high-sVEGFR2, OS was not different according to VEGF (12.1 months, high-VEGF versus 15.1 months, low-VEGF; P = 0.546). Interestingly, the poor prognostic impact of high-VEGF was far significant in patients with low-sVEGFR2 (10.9 months versus 16.8 months; P = 0.036). With this perspective, VEGF/sVEGFR2 ratio was significantly correlated with worse OS in univariate as well as multivariate analysis (HR 1.78 [95% CI 1.08-2.94], P= 0.024). Conclusions: Based on the comprehensive network analysis of CAF, VEGF and sVEGFR2 had distinct CAF signatures in GC. Consideration of both VEGF and sVEGFR2 confers more accurate prognostic implication compared with VEGF alone in GC. Regarding the angiogenic aspect, VEGF/sVEGFR2 ratio is significantly correlated with survival outcome in GC.

TPS780 Background: Life-prolonging systemic therapy such as chemotherapy (FOLFOX, XELOX, FOLFIRI, 5-FU/LV) with / without molecular targeted agents (bevacizumab, afilibercept, cetuximab, panitumumab) are important treatment for metastatic colorectal cancer (mCRC). On the other hand, it is required to establish an evidence of convenient therapy including oral anticancer agent which is expected lower risk of safety. XELIRI was already examined by various doses in this decade, and result of AIO 0604 was regarded as one of the most appropriate regimen. The BIX phase II study showed the tolerability and promising efficacy of the AIO regimen for Japanese mCRC patients (Hamamoto Y, et al. Oncologist 2014). Methods: Asian XELIRI Project (AXEPT) is an East Asian collaborated, open label, randomized phase III clinical trial designed to demonstrate the non-inferiority of XELIRI (+bevacizumab) to the standard of care FOLFIRI (+bevacizumab) as the second-line chemotherapy in patients with mCRC. The primary endpoint is median overall survival. The secondary endpoints are progression-free survival, time to treatment failure, overall response rate, disease control rate, relative dose intensity, safety, correlation between UGT1A1 polymorphisms (*28, *6) and safety. Eligible patients were 20 years of age and older, had histologically proven CRC, ECOG performance status 0-2, adequate organ function, progression or difficult to continue after first line regimen. Patients were randomized 1:1 to standard FOLFIRI (+bevacizuamb 5mg/kg day1), repeated every 14 days (Group A) or XELIRI, Irinotecan 200mg/m2 day1, and capecitabine 1600mg/m2 day 1-14 (+bevacizumab 7.5mg/kg day1), repeated every 21 days (Group B). A Total of 464 events were needed to show non-inferiority with a two-sided α of 0·05 and a power of 80%, a target sample size of 600 patients was required. (The 95% CI upper limit of the hazard ratio was pre-specified as less than 1.3.). Enrollment has started in December 2013. As of August 2015, 98 centers in the Japan, South Korea and China are participating in this trial. Clinical trial information: NCT01996306. UMIN000012263. Clinical trial information: NCT01996306.

411 Background: Host antitumor immunity measured by neutrophil-lymphocyte ratio (NLR) is reported to be associated with prognosis of cancer patients. Standard uptake value (SUV)by18F-FDG PET represents the metabolic activity of tumor itself. The correlation of host immunity and tumor metabolic activity has not been studied. We investigate the association of these two factors and evaluate their roles in prediction of overall survival (OS) in metastatic pancreatic cancer (MPC) patients who receive palliative chemotherapy. Methods: We reviewed 396 MPC patients receivingpalliative chemotherapy. NLR was obtained before initiation of chemotherapy and after 1st cycle of chemotherapy. In 118 patients who were evaluated with 18F-FDG PET before initiation of chemotherapy (PET cohort), maximum SUV (SUVmax) was collected. Cut-offs for each variable were determined by ROC curve. Results: In multivariate analysis, higher NLR was associated with worse OS ( < 2.5, 9.0 m; 2.5-4.4, 7.2 m; ≥ 4.5, 3.9 m; p< 0.001). Reduction of NLR after 1st cycle of chemotherapywas associated with betterOS (8.0 m vs 6.1 m; HR 0.653; p< 0.001). We made the risk scoring model considering both NLR (score 0, NLR < 2.5; score 1, 2.5 ≤ NLR < 4.5; score 2, NLR ≥ 4.5) and ΔNLR(score 0:ΔNLR < 0; score 1: ΔNLR ≥ 0), which identified 4 risk groups with different prognosis (group with risk score 0 vs 1 vs 2 vs 3: OS 9.7 vs 7.9 vs 5.7 vs 2.6 months; HR 1 vs 1.329 vs 2.137 vs 7.915, respectively; P < 0.001). In PET cohort (118 patients), NLR and SUVmax were independent prognostic factors for OS. The risk model considering both NLR (score 0, NLR < 2.5; score 1, 2.5 ≤ NLR < 4.5; score 2, NLR ≥ 4.5) and SUVmax (score 0:SUVmax < 4.5; score 1: SUVmax ≥ 4.5), which define 4 risk groups with different OS. (group with risk score 0 vs 1 vs 2 vs 3: OS 11.8 vs 9.8 vs 7.2 vs 4.6 months; HR 1 vs 1.536 vs 2.958 vs 5.336, respectively; P < 0.001). Conclusions: NLR and SUVmax as simple parameters of host antitumor immunity and tumor metabolic activity, respectively, have significant impacts on the survival of metastatic pancreatic cancer patients independently. Consideration of both aspects allows more precise prediction of patients’ prognosis.

Introduction Neutrophil to lymphocyte ratio (NLR) and standard uptake value (SUV) by 18F-FDG PET represent host immunity and tumor metabolic activity, respectively. We investigated NLR and maximum SUV (SUVmax) as prognostic markers in metastatic pancreatic cancer (MPC) patients who receive palliative chemotherapy. Methods We reviewed 396 MPC patients receiving palliative chemotherapy. NLR was obtained before and after the first cycle of chemotherapy. In 118 patients with PET prior to chemotherapy, SUVmax was collected. Cut-off values were determined by ROC curve. Results In multivariate analysis of all patients, NLR and change in NLR after the first cycle of chemotherapy (ΔNLR) were independent prognostic factors for overall survival (OS). We scored the risk considering NLR and ΔNLR and identified 4 risk groups with different prognosis (risk score 0 vs 1 vs 2 vs 3: OS 9.7 vs 7.9 vs 5.7 vs 2.6 months, HR 1 vs 1.329 vs 2.137 vs 7.915, respectively; P

Introduction Racial disparities in incidence rate as well as risk factors for venous thromboembolism (VTE) exist between Asian and Western populations. Moreover, predictors for recurrent VTE were not identified in Asians. Thus, this study was undertaken to investigate risk factors for recurrent VTE events in Korean people. Materials and Methods Three hundred-three patients newly diagnosed as VTE were enrolled from Seoul National University Hospital. Recurrence rate based on risk factors for VTE were investigated. Cumulative incidence of recurrent VTE was calculated by the Kaplan and Meier method. Independent predictors for VTE were determined using Cox proportional hazards model. Results After a median follow-up of 44 months, 24 (8%) of 303 patients relapsed for a total observation time of 1,217 patient-year. Cumulative incidences of recurrent VTE were 3% at 1 year, 10% at 5 years, and 18% at 8 years. Independent predictors for recurrent VTE were presence of residual thrombosis (hazard ratio [HR] = 3.1, 95% confidence interval [CI] 1.0–9.3; p = 0.044), antiphospholipid syndrome (APS) (HR = 4.3, 95% CI 1.0–19.0; p = 0.052), and age 50 years or younger (HR = 2.5, 95% CI 1.0–6.6; p = 0.053) by multivariate analysis. Residual thrombosis and APS remained predictive of recurrence by the anticoagulation-period stratified analysis. Conclusions In contrast to Western populations, Korean patients with VTE had the lower recurrent rate. Extended anticoagulation is necessary for Korean patients with residual thrombosis or APS.

Mucoepidermoid carcinoma (MEC) of lung is a rare malignancy of lung which originates from minor salivary glands of tracheobronchial tree. EGFR targeted therapy by inhibition of EGFR activation with the specific tyrosine kinase inhibitors (TKIs) has shown meaningful anti-tumor activity in patients with EGFR TK mutation and/or amplification, or in patients with adenocarcinoma. In the present study, we find that MEC has EGFR mutation in 40% (2 out of 5) of cases, and all mutations are L858R mutation. In addition, we also observed that a MEC patient well-responded to EGFR TKI in the absence of EGFR mutation or amplification. These data indicate for the first time that MEC of lung is another potential target of EGFR inhibitor, and more extended clinical investigation is warranted.

Background The objective of this study was to evaluate the efficacy and toxicity of infusional 5-fluorouracil (5-FU), folinic acid and oxaliplatin (modified FOLFOX-6) in patients with advanced gastric cancer (AGC), as first-line palliative combination chemotherapy. We also analyzed the predictive or prognostic value of germline polymorphisms of candidate genes associated with 5-FU and oxaliplatin. Methods Seventy-three patients were administered a 2 hour infusion of oxaliplatin (100 mg/m2) and folinic acid (100 mg/m2) followed by a 46 hour continuous infusion of 5-FU (2,400 mg/m2). Genomic DNA from the patients' peripheral blood mononuclear cells was extracted. Ten polymorphisms within five genes were investigated including TS, GSTP, ERCC, XPD and XRCC. Results The overall response rate (RR) was 43.8%. Median time to progression (TTP) and overall survival (OS) were 6.0 months and 12.6 months, respectively. Toxicities were generally tolerable and manageable. The RR was significantly higher in patients with a 6-bp deletion homozygote (-6 bp/-6 bp) in TS-3'UTR (55.0% vs. 30.3% in +6 bp/+6 bp or +6 bp/-6 bp, p = 0.034), and C/A or A/A in XPD156 (52.0% vs. 26.1% in C/C, p = 0.038). The -6 bp/-6 bp in TS-3'UTR was significantly associated with a prolonged TTP and OS. In a multivariate analysis, the 6-bp deletion in TS-3'UTR was identified as an independent prognostic marker of TTP (hazard ratio = 0.561, p = 0.032). Conclusion Modified FOLFOX-6 chemotherapy appears to be active and well tolerated as first line chemotherapy in AGC patients. The 6-bp deletion in TS-3'UTR might be a candidate to select patients who are likely to benefit from 5-FU based modified FOLFOX-6 in future large scale trial.

Introduction: Regorafenib is an oral multikinase inhibitor, which has anti-angiogenic and anti-tumor activity by inhibition of a number of angiogenic and oncogenic kinases. It induces distinct radiological changes in metastatic colorectal cancer (mCRC), which are decrease in tumor attenuation and cavitation of lung metastasis. These changes may be a result of anti-angiogenic activity, but the clinical implications of the changes are unclear. This study was designed to analyze the radiological changes in association with treatment outcome in mCRC patients treated with regorafenib. Methods: All patients were a part of a main study entitled Identification of Predictive Biomarker of Regorafenib in Refractory Colorectal Cancer: A Prospective Explorative Study (NCT01996969). Tumor attenuation measured by Hounsfield units (HU) of contrast-enhanced computed tomography (CT) scan and cavitary changes of lung metastases were evaluated in mCRC patients (N = 80) treated with regorafenib (160mg orally once daily, on days 1-21 of a 28-day cycle). Maximum standardized uptake values (mSUV) of tumor lesions at baseline and after 2 cycles of treatment were analyzed in patients whose 18-fluoro-deoxyglucose positron emission tomography (PET)-CT images were available for analysis. Treatment outcome was evaluated according to the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. The association between radiological changes and treatment outcome was analyzed. Results: A total of 141 lesions in 72 patients were analyzed with HU measurement. After 2 cycles of regorafenib treatment, 87.5% of patients had a decrease in tumor attenuation. Median change in tumor attenuation was -23.9% (range -61.5% to 20.7%). Lesional attenuation changes were modestly associated with changes in mSUV in PET-CT scans (Pearson's r = 0.38, p Conclusions: Regorafenib showed prominent anti-angiogenic activity in mCRC represented by the radiological changes. Although the changes were not associated with treatment outcome, it was persistently observed at the time of PD by RECIST 1.1. The results suggest the possibility of inadequacy of current conventional response evaluation paradigm in treating mCRC patients with regorafenib. We may need to develop alternative evaluation and treatment strategies considering the anti-angiogenic activity. Citation Format: Yoojoo Lim, Sae-Won Han, Jeong Hee Yoon, Jeong Min Lee, Jung Min Lee, Jin Chul Paeng, Jae-Kyung Won, Gyeong Hoon Kang, Seung-Yong Jeong, Kyu Joo Park, Kyung-Hun Lee, Jee Hyun Kim, Tae-You Kim. Clinical implications of anti-angiogenic effect of regorafenib in metastatic colorectal cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A2.

In order to identify novel fusion transcripts in colorectal cancer, we carried out paired-end RNA sequencing in 28 human colorectal cancer cell lines. Fusion transcript candidates were identified using ChimeraScan and FusionMap tools. We obtained 1380 candidates having 4 or more read counts and spanning reads. Among the candidates, we selected 27 candidates for validation which harbors genes related to the Wnt signaling pathway or kinases according to KEGG or DAVID. After the targeted gene filtering step, validation using RT-PCR with fusion specific primers finally resulted in 2 intra- and 1 inter-fusion transcripts. Intra-fusion transcripts were NFATC3-PLA2G15 and AKAP13-PDE8A and inter-fusion transcript was KRT8-PKM2 each identified in colo-320, SW-480 and SNU-1235, respectively. The fusion junctions were confirmed by Sanger sequencing. NFATC3-PLA2G15 fusion transcripts consisted of exon 1-9 of NFATC3 (nuclear factor of activated T-cells, cytoplasmic 3) gene and exon 2-6 of the PLA2G15 (Phospholipase A2, Group 5) gene and both located on the same chromosome 16q. NFATC3 is known as transcription factor in the Wnt signaling pathway and regulates function of the target genes like cell proliferation, invasion and epithelial-to-mesenchymal transition (EMT). Under the experiments using siRNA in the colo-320 cell carrying fusion transcript, knockdown of the NFATC3-PLA2G15 fusion transcript decreased mRNA and protein expression of mesenchymal markers, namely vimentin (VIM), Twist-related protein 1 (TWIST1) and fibronectin (FN), and increased epithelial markers, E-cadherin (CDH1) and claudin-1 (CLDN1). Fusion transcripts knockdown also led to decrease of the invasion ability regulated by above markers. Moreover, soft agar assay showed inhibition of colony formation after fusion transcript knockdown. Fusion transcript downregulation also resulted in decrease of cell proliferation and mRNA and protein expression of cyclin D but increase in p27 level. The knockdown did not have influence in the fusion negative cell line. Collectively, these results suggest that the NFATC3-PLA2G15 fusion transcript is involved in invasion and proliferation of colorectal cancer cells. Citation Format: JE Jang, HP Kim, SH Lee, DW Lee, YJ Lim, SW Han, TY Kim. NFATC3-PLA2G15 fusion transcript identified by RNA-sequencing promotes tumor progression in colorectal cancer cells. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A28.

Background Although genomic data of CRC continue to accumulate, only limited information on prognostic role of the alterations have been reported. We have analyzed the prognostic impact of the key mutations in CRC using next generation sequencing technology. Methods We selected 40 genes from 5 critical pathways (WNT, TGF-B, PI3K, RTK-RAS and P53) of CRC based on TCGA data. Homogenous population of CRC patients were used to investigate the prognostic implication: 188 stage III or high-risk stage II CRC patients treated with curative surgery followed by adjuvant 5-fluorouracil/ leucovorin/oxaliplatin (FOLFOX) chemotherapy. Archival tissue from Seoul National University Hospital Tumor Bank was used. The target (size 109kb) enrichment process was proceeded base on in-solution hybridization with biotinylated probes. The captured library was amplified and sequenced using Hiseq 2500 (Illumina, USA). Sequencing data was aligned to GRCh37 and variant call and somatic analysis processes was performed by VarScan2 and were annotated with ANNOVAR. Using somatic nonsynonymous mutation data, we selected mutant gene signature which is associated with prognosis. We used binary collapsing method in a forward stepwise selection method to combine mutated genes. Test statistics were obtained from Cox-proportional hazard model. Two-sided p-values of less than 0.05 were considered statistically significant. Results Among a total of 188 patients, 63 had tumor in proximal location and 125 had tumor in distal location. Tumor stage was high-risk stage II in 21 patients and III in 167 patients. Average coverage of the total samples was 417X (414X tumor and 420X normal mucosa). Mutation frequencies were similar with the TCGA data except for NRAS and DKK2, having lower frequency in the present study. During a median follow-up duration of 58 months, 45 relapse and 23 death events have occurred. Alteration in individual gene or pathway did not have prognostic significance in terms of disease free survival (DFS) and overall survival (OS). By using binary collapsing method, we identified a 4 gene signature comprising ACVR1B, ERBB2, LRP5, and KRAS. 89 patients (47.3%) had 1 or more mutation in these 4 genes. 4 gene mutant group had worse DFS and OS compared with 4 gene wild type group. 3-year DFS and 5-year OS was 72.8% and 82.5% in mutant group compared with 88.7% and 96.0% in wild type group (p-values 0.004 and 0.001, respectively). Multivariate analysis revealed 4 gene signature as an independent negative prognostic factor of DFS and OS (adjusted hazard ratios 2.48 and 4.26, respectively). Conclusion Mutations in the 4 genes (ACVR1B, ERBB2, LRP5, and KRAS) were associated with poor prognosis in CRC patients treated with surgery followed by adjuvant FOLFOX chemotherapy. Validation study in an independent cohort is currently underway. Citation Format: Dae-Won Lee, Yongjun Cha, Sae-Won Han, Si-Hyun Lee, Hwang-Phill Kim, Jaemyun Lyu, Hyojun Han, Hyoki Kim, Hoon Jang, Duhee Bang, Iksoo Huh, Taesung Park, Jeong Mo Bae, Jae-Kyung Won, Seung-Yong Jeong, Kyu Joo Park, Gyeong Hoon Kang, Tae-You Kim. Mutation signature associated with colorectal cancer prognosis identified by targeted next-generation sequencing. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A72.

Introduction: Pim kinases are highly conserved serine/threonine kinases that control proliferation and survival pathways in cancer cells. Different expression patterns of each isoforms (Pim-1, Pim-2, and Pim-3) have been observed in various types of human cancer including gastric cancer. AZD1208 is a potent and selective inhibitor that affects all three isoforms of Pim. We investigated the effect of AZD1208 as a single agent or in combination with an Akt inhibitor on the growth and cell death in gastric cancer cells. Materials and Methods: The antitumor activity of AZD1208 with/without an Akt inhibitor was evaluated in a large panel of gastric cancer cell lines through growth inhibition assay. The underlying mechanism was also examined by western blotting, immunofluorescence assay (IFA), and cell cycle analysis. Results: Direct substrates of Pim kinases were downregulated by the treatment with AZD1208, but we could not find any reduction of cell viability in short-term cell cultures. In contrast, cell viability decreased significantly in long-term cultures. Light chain 3B (LC3B), a marker for autophagy, increased in sensitive cells in dose dependent manner with AZD1208 treatment, which suggest that the growth inhibition effect of AZD1208 was achieved through autophagy, but not through apoptosis. Moreover, we found that ATM and Chk2, two critical components of the DNA repair pathway, were activated in an AZD1208-resistant cell line. We also confirmed that the combination of an Akt inhibitor with AZD1208 produced a highly synergistic effect in gastric cancer cell lines. Conclusion: AZD1208 induced cell death through autophagy in gastric cancer cells. Additionally, the combination of AZD1208 with an Akt inhibitor shows synergistic antitumor effects. Citation Format: Miso Lee, Kyung-Hun Lee, Ahrum Min, Jungeun Kim, Seock-Ah Im, Seon-Gyeong Kim, Hyemin Jang, Yae-Won Yang, Tae-Yong Kim, Sae-Won Han, Do-Youn Oh, Tae-You Kim, Yung-Jue Bang. Pan-pim kinases inhibitor, AZD1208 suppresses tumor growth and synergistically interacts with an AKT inhibitor in gastric cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2422. doi:10.1158/1538-7445.AM2015-2422

Purpose Regorafenib is an orally bioavailable, small molecular multikinase inhibitor of VEGFR, PDGFR, FGFR, KIT, RET, BRAF, BRAFV600E, CRAF, and TIE2. Although regorafenib has demonstrated survival benefits in patients with metastatic colorectal and gastrointestinal stromal tumors, there is no proven biomarker predicting sensitivity to regorafenib. We investigated preclinical activity of regorafenib in gastric and colorectal cancer cell-lines to identify genetic alterations associated with sensitivity to regorafenib. Methods Fourteen gastric cancer cell lines and 18 colorectal cancer cell lines were screened for regorafenib sensitivity with cell proliferation assays. We performed targeted exome and transcriptome sequencing of the cell lines to identify genetic alterations associated with sensitivity to regorafenib. Mechanisms of regorafenib sensitivity were investigated in regorafenib sensitive cell lines with immunoblotting and flow cytometry. Results Two gastric (SNU-16, KATO-III) and 1 colorectal (NCI-H716) cancer cells were sensitive to regorafenib with GI50 values of less than 1 μM. Mutation profiles and mRNA expression levels of regorafenib target molecules in regorafenib sensitive and insensitive cell lines demonstrated that amplification of FGFR2 was the only genetic alteration associated with in vitro sensitivity to regorafenib. FGFR2 amplified gastric (SNU-16, KATO-III) and colorectal (NCI-H716) cancer cell lines revealed activated signaling through FGFR2 pathway, and knock-down of FGFR2 with siRNA significantly repressed cellular growth rate and decreased sensitivity to regorafenib. Regorafenib effectively inhibited phosphorylation of FGFR2 and its downstream signaling molecules in dose-dependent manner selectively in FGFR2 amplified cells. In cell cycle analysis, regorafenib induced G1/S arrest (SNU-16, KATO-III) and apoptosis (NCI-H716), however no significant changes were seen in cell lines without FGFR2 amplification. Conclusions Signaling through FGFR2 pathway plays a key role in cellular growth and survival in FGFR2 amplified cancers. Regorafenib effectively abrogates activated FGFR2 signaling in FGFR2 amplified gastric and colorectal cancer cells, and therefore should be considered for integration into treatment in patients with FGFR2 amplified gastric and colorectal cancers. Citation Format: Yongjun Cha, Hwang-Phill Kim, Sae-won Han, Jiyeon Yun, Sang-Hyun Song, Tae-You Kim. FGFR2 amplification is predictive of sensitivity to regorafenib in gastric and colorectal cancers. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5484. doi:10.1158/1538-7445.AM2015-5484

Background: JAB1 (c-Jun activation domain binding protein-1) is a c-Jun coactivator, also known as COP9 signalosome subunit 5 (CSN5). Jab1 has an important role in cell proliferation and apoptosis. Overexpression of Jab1 is correlated with poor prognosis in various cancers. Biliary tract cancer (BTC) has a poor prognosis with a huge unmet medical need. The role of Jab1 has not been studied in BTC. We investigated the role and mechanism of Jab1 as a potential therapeutic target in BTC. Methods: We used 8 kinds of BTC cells and designed Jab1 siRNA. MTT assay and colony formation assay were done to determine growth inhibitory effect of Jab1 knockdown. Cell cycle analysis was done by FACS Calibur flow cytometer and cell migration was evaluated by wound healing assay. We used cycloheximide chase assay for measuring of protein half-life. Results: BTC cell lines showed high level of Jab1 expression. Among them, SNU478, SNU869 and SNU 1196 were indicated with especially higher level of Jab1 expression. Cell growth and proliferation of BTC cells were decreased by Jab1 knockdown. Depletion of Jab1 induced G1 arrest, as well as decreased CyclinD/CyclinA and increased p27. Cell migration was also inhibited by Jab1 knockdown. Inhibition of Jab1 showed the decrease of pSrc, pAkt. Interestingly, depletion of Jab1 led to the elevation of PTEN protein levels without change of PTEN mRNA levels. PTEN half-life was longer in Jab1 siRNA-transfected cells. Suppression of Jab1 increased the sensitivity of BTC cells to the cytotoxic chemotherapeutic agent. Conclusion: Suppression of Jab1 shows antitumor effects in BTC cells by inhibiting cell proliferation, migration, cell cycle and increase of chemosensitivity. Taken together, Jab1 might be a potential therapeutic target in BTC. Citation Format: Ah-Rong Nam, Kyo Hwa Kang, Ji Eun Park, Ju-Hee Bang, Ling Jin, Mei Hua Jin, Tae Yong Kim, Sae-Won Han, Sang-Hyun Song, Seock-Ah Im, Tae-You Kim, Do-Youn Oh, Yung-Jue Bang. The role and mechanism of JAB1 as a therapeutic target in biliary tract cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1714. doi:10.1158/1538-7445.AM2015-1714

Introduction: The DNA repair system is critical for maintaining genomic integrity. In particular, the homologous recombination (HR) repair pathway, on that repairs DNA double-strand breaks (DSBs), is directly associated with cancer development. Many cancer cells could contain mutations in genes involved in the HR pathway including BRCA1/2, ATM, ATR, and RAD51. ATR can be activated by various types of DNA damage and it initiates DNA damage-induces signaling cascade. As a result, ATR pathway components are considered promising therapeutic targets because ATR inhibition is likely to have greater deleterious effect on cancer cells. Materials and Methods: The antiproliferative activity of AZD6738 was examined in vitro using a cytotoxic assay, cell cycle analysis, and western blotting. To figure out the action mechanism of AZD6738 in gastric cancer cells, the expression of proteins which participate in DNA repair were investigated. The accumulation of DNA damage was also assessed with a DNA comet assay. These in vitro data were validated in vivo using a human gastric cancer xenograft model. Results: Human gastric cancer cell lines showed heterogeneous response to AZD6738. In AZD6738 sensitive cells, ATR inhibition leads to the accumulation of unrepaired DSBs due to dysfunctional RAD51 foci formation along with increased caspase 3-dependent cell death and S phase cell cycle arrest. Compared with sensitive cells, the activation of ATM-chk2 signaling pathway under the ATR inhibition was observed in the AZD6738 insensitive cells. It suggests that the activation of ATM-chk2 signal leads to attenuation of AZD6738 sensitivity. Furthermore, AZD6738 significantly suppressed tumor growth with increased apoptosis in vivo. Conclusion: We evaluated the anti-tumor activity of AZD6738 in gastric cancer in vitro and in vivo model. This is the first study to show that AZD6738 interferes with RAD51-mediated homologous recombination, as well as promotes cell death by inducing S cell cycle arrest and apoptosis in gastric cancer cells. Our findings can help to promote novel treatment strategies using AZD6738 in gastric cancer. Citation Format: Ahrum Min, Seock-Ah Im, Hyemin Jang, Seongyeong Kim, Miso Lee, Jungeun Kim, Kyung-Hun Lee, Sae-Won Han, Tae-Young Kim, Do-Youn Oh, Tae-You Kim, Woo-Ho Kim, Yung-Jue Bang. Targeting ATR using a novel ATR inhibitor AZD6738 in human gastric cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-107. doi:10.1158/1538-7445.AM2015-LB-107

Background: HER2 is the first validated therapeutic target in advanced gastric cancer (GC). Trastuzumab in combination with chemotherapy is used as a first-line treatment of GC. The resistance mechanisms to trastuzumab have not been widely known in GC. We investigated the resistance mechanisms to HER2-targeting agents in HER2-positive gastric cancer cells. Methods: SNU216 and NCI-N87 are HER2 amplified gastric cancer cells. Using these cells, we established trastuzumab-resistant cells (SNU216-HR, N87-HR) and dacomitinib (panHER inhibitor)-resistant cells (SNU216-PR). Acquired resistance of the established cell lines was verified by MTT assay and western blotting. We compared various receptor tyrosine kinase activities and protein expression levels between parental and resistant cells by RTK arrays and western blotting. We used many targeted agents (HER family inhibitor, PI3K inhibitor, mTOR inhibitor, MEK inhibitor, Src inhibitor, HSP90 inhibitor, etc) to overcome the resistance. Results: Resistant cells displayed more rapid growth rate and different morphology compared with parent cells. Resistant cells showed increased levels of pEGFR, pHER2, pHER3, pMET, pIGF1R, pAXL, pSTAT3, pAKT, pFAK, and TS compared with the parental cells in western blot. With the treatment of trastuzumab, HR cells showed elevated levels of EGFR, pHER2, AXL, pAXL, pMEK, pSRC, pSTAT3, pAKT, pERK and TS compared with the parental cells. With the treatment of dacominitib, PR cells showed elevated levels of pEGFR, pAXL, pIGF1R, pMEK, pSRC, pERK and TS compared with the parental cells in western blot. The RTK arrays also showed the similar findings. These resistant cells were more sensitive to Src inhibitor and PI3K inhibitor than parent cells. Conclusion: Resistance mechanisms to HER2-targeting strategy in gastric cancer include activation of HER, MET, FAK and Src pathway. Targeting these pathways is needed to overcome resistance. Citation Format: Kyo Hwa Kang, Ah-Rong Nam, Ji Eun Park, Ju-Hee Bang, Jin Ling, Mei Hua Jin, Tae Yong Kim, Sae-Won Han, Sang-Hyun Song, Seock-Ah Im, Tae-You Kim, Do-Youn Oh, Yung-Jue Bang. Resistance mechanisms to HER2-targeting treatment in HER2-positive gastric cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3599. doi:10.1158/1538-7445.AM2015-3599

3576 Background: The purpose of this randomized phase III trial was to evaluate the addition of synthetic 3-hydroxy-3methyglutaryl coenzyme A (HMG-CoA) reductase inhibitor, simvastatin to XELIRI/FO...

11094 Background: Programmed death-ligand 1 (PD-L1) expression in cancer cells or tumor microenvironment is under investigation as a candidate biomarker in the new drug development of immuno-oncolo...

4050 Background: Trastuzumab-based chemotherapy is standard treatment for HER2-positive advanced gastric cancer (AGC). Although increased HER2 gene amplification by fluorescent in situ hybridizatio...

Background: The association of epidermal growth factor receptor (EGFR) mutations with the response to conventional cytotoxic chemotherapeutic agents in non-small-cell lung cancer patients has not been investigated. We retrospectively analyzed the associations between response to chemotherapy and molecular markers associated with gefitinib responsiveness including EGFR mutations. Methods: EGFR (exons 18, 19 and 21) and K-ras mutations (exon 2) were studied by direct sequencing and p-Erk and p-Akt expressions were studied by immunohistochemistry in archival paraffin embedded tissues. Response rate (RR) and time-to-progression (TTP) of prior chemotherapy by platinum, paclitaxel and gemcitabine were analyzed with respect to the presence of EGFR and K-ras mutations, and p-Erk and p-Akt expressions. Results:Of90patientsinvestigated,75receivedplatinumsand45receivedpaclitaxelasfirst-line chemotherapyagents.TheRRS andTTPS ofplatinum-andpaclitaxel-containingregimenswere not affected by EGFR or K-ras mutations, nor by p-Erk or p-Akt expression. Fifty-seven patients received gemcitabine as first- or second-line chemotherapy. RR was not affected by EGFR or Kras mutations or by p-Akt expression. However, all responders to gemcitabine exhibited (+) p-Erk expression [RR 30.6% for p-Erk (+) versus 0% for p-Erk (� ), P = 0.01]. TTP was not affected by EGFR or K-ras mutations or by p-Erk or p-Akt expression. Conclusions: EGFR mutations did not affect response to conventional chemotherapeutic agents, namely platinums, paclitaxel and gemcitabine. Our results also suggest that it may be undesirable to use gemcitabine in patients with tumors not expressing p-Erk.

Clinical predictors including Asian, female, adenocarcinoma and never-smoker and epidermal growth factor mutation are associated with gefitinib responsiveness in non-small-cell lung cancer. Direct comparison between clinical predictors and EGFR mutation for their predictive power has not been reported.For 120 Korean NSCLC patients treated with gefitinib, we have analyzed EGFR mutational status in exons 18, 19 and 21. Patients were grouped according to the number of clinical predictors (female, adenocarcinoma and never-smoker). Response rate (RR), time-to-progression (TTP) and overall survival (OS) were analyzed. Multivariate analysis was performed to investigate which approach yielded better prediction.RRs according to number of clinical predictors were 0: 3.4%, 1: 17.1%, 2: 29.4% and 3: 33.3% (p=0.002). Patients with gefitinib-sensitive EGFR mutation showed 61.9% RR compared with 12.1% in the remaining patients (p0.001). RRs were higher in patients with the EGFR mutations regardless of the number of clinical predictors. In multivariate analysis, gefitinib-sensitive EGFR mutation showed higher odds ratio of response (9.6, 95% confidence interval [CI] 3.2-28.7) compared with number of clinical predictors (1.7, 95% CI 1.1-2.7). Hazard ratio (HR) of TTP was also better in gefitinib-sensitive EGFR mutation (0.24, 95% CI 0.12-0.47) than number of clinical predictors (0.83, 95% CI 0.69-0.99). Only gefitinib-sensitive EGFR mutation was associated with improved OS (HR 0.25, 95% CI 0.12-0.52).EGFR mutation should be analyzed whenever possible for effective prediction of objective benefit from gefitinib in NSCLC patients with one or more clinical predictors.

Gefitinib has shown meaningful antitumor activity with tolerable toxicity in chemotherapy-refractory NSCLC in previous studies. Moreover, EGFR expression failed to show a correlation with response. In an attempt to identify predictive markers of response, we have investigated the tumoral expression of key signaling molecules of EGFR (EGFR, p-EGFR, p-Akt, p-Erk, p-STAT3) by immunohistochemistry and analyzed their correlations with response. Of 65 patients who received gefitinib (250 mg/day) for chemotherapy-refractory NSCLC, there were 14 partial responses (21.5%), 21 stable diseases (32.3%) and 21 progressive diseases (32.3%). Median durations of overall survival and time to progression were 6.7 months and 2.8 months, respectively. Immunohistochemistry was performed in 34 patients with evaluable tissue specimens. EGFR was overexpressed (2+ or 3+) in 32.4% and p-EGFR was positive in 26.5%. The expressions of p-Akt, p-Erk and p-STAT3 were positive (1+ or 2+) in 50%, 38.2% and 79.4%, respectively. The EGFR expression was not correlated with p-EGFR or the downstream molecules. EGFR or p-EGFR status did not correlate with response. Positive expression of p-Erk was significantly associated with poor response (38.1% in -, 14.3% in 1+, 0% in 2+; p = 0.046). Furthermore, tumors with positive p-Akt and negative p-Erk nuclear expression exhibited the best response (60%), whereas there was no response in the opposite [p-Akt (-), p-Erk (+)] cases. Intense nuclear staining of p-Akt (2+) was associated with prolonged TTP (HR 0.25, 95% confidence interval [CI] 0.08-0.79, p = 0.018) and OS (HR 0.16, 95% CI 0.04-0.62, p = 0.008). These results support the assumption that gefitinib responsiveness might be predicted by activated EGFR downstream molecules such as p-Akt and p-Erk.

415 Background: Ampulla of Vater cancer (AoV ca) is rare tumor, and its adjuvant treatment after curative resection has not been well established. The purpose of this study is to see the clinical outcomes of curatively resected AoV ca patients and to figure out the role of adjuvant treatment. Methods: We reviewed 227 AoV ca patients who underwent curative resection at the Seoul National University Hospital between 1997 and 2012. Clinical factors, pathologic findings, adjuvant treatment pattern, disease-free survival (DFS) and overall survival (OS) were analyzed. Results: Median age was 61.5 year old (range, 33.8-88.2) and 125 patients were male. T1/T2 stage was found in 63.9% of patients and T3/4 stage was in 36.1%. Seventy-seven patients (33.9%) had node positive disease (N+) and seventy-three patients (32.1%) had well-differentiated histology. OS of all patients was 90.9 months (95% CI: 58.4-128.09). 5-Year OS- and DFS- rate were 58.2% and 62.5%, respectively. On multivariate analysis, adverse prognostic factors for OS included poorly differentiated histology (HR 1.35, 95% CI: 1.01-1.81, p=0.045), elevated CEA (HR 2.55, 95% CI: 1.29-5.04, p=0.007), elevated CA 19-9(HR 1.86, 95% CI: 1.08-3.21, p=0.027), and stage (HR 2.34, 95% CI: 1.43-3.82, p=0.001). A total of 104 patients (46.3%) received adjuvant treatment (concurrent chemoradiotherapy (CCRT) 32, CCRT with maintenance chemotherapy 58, chemotherapy alone 9, radiotherapy alone 5). Most of the chemotherapies were 5-FU-based ones. Among patients with T1/T2 & N (-) (n=111), only 25 patients (22.5%) received adjuvant treatment. In contrast, among patients with T3/T4 or N (+) (n=116), 79 patients (68.1%) received adjuvant treatment. 5Y-OS rate was 74.1% in patients with T1/T2 and N (-) and that of patients with T3/T4 or N (+) was 43.0% (p

83 Background: Weight loss during chemotherapy is a significant prognostic factor for poor survival in patients advanced gastric cancer (AGC). However, in most studies, weight loss was measured at the end of chemotherapy, limiting its clinical use. In this study, we evaluated whether weight loss during the first month of chemotherapy could predict survival outcomes in patients with AGC. Methods: We analyzed 719 patients with metastatic or recurrent AGC who were receiving palliative chemotherapy. We calculated initial body mass index (BMIi), percent weight loss after one month of chemotherapy (ΔW1m), percent weight loss after last administration of chemotherapy (ΔWend), and average weight loss per month during chemotherapy (ΔW/m). We correlated these data with overall survival (OS) by receiver operating characteristic (ROC) curves and Kaplan-Meier curves, and performed a subgroup analysis using Cox regression. Results: The probabilities of longer OS had stronger correlations with ΔW/m and ΔW1m than with ΔWend or BMIi. The optimal cutoff values of ΔW/m and ΔW1m for predicting shorter survival were 1% and 3%, respectively. A significant positive correlation between ΔW1m and ΔW/m (r2 = 0.591, p < 0.001) was observed. Patients with ΔW1m more than 3% significantly younger, had worse performance status, more diffuse-type Lauren classification, more HER2-negative pathology, a higher number of involved organs, and more peritoneal seeding at initial presentation. OS of patients with ΔW1m more than 3% were significantly shorter than patients with less weight loss (ΔW1m ≥3%: 9.7