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Background: The current first-line (1L) standard of care (SOC) for human epidermal growth factor receptor 2-positive (HER2+) metastatic breast cancer (MBC) is trastuzumab (T) plus pertuzumab (P) and a taxane. Despite advances in 1L SOC, most patients (pts) progress during maintenance therapy with T+P. Tucatinib is a tyrosine kinase inhibitor (TKI) approved in combination with T and capecitabine for adults with HER2+ MBC, with and without brain metastases (BM). In HER2CLIMB, the addition of tucatinib significantly prolonged progression-free survival (PFS) and overall survival (OS) in pts with HER2+ MBC and was well tolerated. Adding tucatinib also reduced the risk of disease progression or death in pts with untreated and/or active BM (Murthy et al. 2020, Curigliano et al. 2021). HER2CLIMB-05 investigates whether adding tucatinib to 1L SOC as maintenance therapy will extend PFS while maintaining quality of life (QOL). Methods: HER2CLIMB-05 (NCT05132582) is a phase 3, randomized, double-blind study evaluating tucatinib plus T+P as maintenance therapy for HER2+ MBC. Approximately 650 pts will be enrolled. Eligible pts will have advanced HER2+ disease, no progression on 4–8 cycles of prior 1L SOC, ECOG Performance Status of 0 or 1, and no or asymptomatic BM. Exclusion criteria include prior treatment with anti-HER2 and/or anti-epidermal growth factor receptor TKI (prior SOC for early BC is permitted) or inability to undergo contrast magnetic resonance imaging of the brain. Pts will be randomized 1:1 to receive either tucatinib or placebo twice daily, with T+P once every 21 days. Pts with HR+ disease may receive endocrine therapy. The primary endpoint is investigator-assessed PFS. Secondary endpoints include OS (key endpoint), time to deterioration of health-related QOL, central nervous system PFS, safety, and pharmacokinetic (PK) parameters. PFS and OS will be compared using a 2-sided stratified log-rank test between treatment groups. Time-to-event endpoints will be summarized using the Kaplan–Meier method. PK and safety data will be summarized using descriptive statistics. Enrollment is ongoing in the US, with additional sites planned. Citation Format: Erika Hamilton, Junji Tsurutani, Giuseppe Curigliano, Miguel Martín, Ciara C. O’Sullivan, Joo Hyuk Sohn, Konstantinos Tryfonidis, Libero Santarpia, Shan Yang, Véronique Diéras. Phase 3 study of tucatinib or placebo in combination with trastuzumab and pertuzumab as maintenance therapy for HER2+ metastatic breast cancer (HER2CLIMB-05, trial in progress) [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 OT2-16-03.

Background: The current first-line (1L) standard of care (SOC) for human epidermal growth factor receptor 2-positive (HER2+) metastatic breast cancer (MBC) is trastuzumab (T) plus pertuzumab (P) and a taxane. Despite advances in 1L SOC, most patients (pts) progress during maintenance therapy with T+P. Tucatinib is a tyrosine kinase inhibitor (TKI) approved in combination with T and capecitabine for adults with HER2+ MBC, with and without brain metastases (BM). In HER2CLIMB, the addition of tucatinib significantly prolonged progression-free survival (PFS) and overall survival (OS) in pts with HER2+ MBC and was well tolerated. Adding tucatinib also reduced the risk of disease progression or death in pts with untreated and/or active BM (Murthy et al. 2020, Curigliano et al. 2021). HER2CLIMB-05 investigates whether adding tucatinib to 1L SOC as maintenance therapy will extend PFS while maintaining quality of life (QOL). Methods: HER2CLIMB-05 (NCT05132582) is a phase 3, randomized, double-blind study evaluating tucatinib plus T+P as maintenance therapy for HER2+ MBC. Approximately 650 pts will be enrolled. Eligible pts will have advanced HER2+ disease, no progression on 4-8 cycles of prior 1L SOC, ECOG Performance Status of 0 or 1, and no or asymptomatic BM. Exclusion criteria include prior treatment with anti-HER2 and/or anti-epidermal growth factor receptor TKI (prior SOC for early BC is permitted) or inability to undergo contrast magnetic resonance imaging of the brain. Pts will be randomized 1:1 to receive either tucatinib or placebo twice daily, with T+P once every 21 days. Pts with HR+ disease may receive endocrine therapy. The primary endpoint is investigator-assessed PFS. Secondary endpoints include OS (key endpoint), PFS by blinded independent central review (BICR), time to deterioration of health-related QOL, central nervous system PFS, safety, and pharmacokinetic (PK) parameters. PFS and OS will be compared using a 2-sided stratified log-rank test between treatment groups. Time-to-event endpoints will be summarized using the Kaplan-Meier method. PK and safety data will be summarized using descriptive statistics. Enrollment is ongoing in the US, Canada, and several EU and APAC countries, with additional sites planned. This abstract was previously presented at ESMO-BC 2022, FPN (Final Publication Number): 415, by Veronique Dieras (reused with permission). Citation Format: Erika Hamilton, Junji Tsurutani, Joohyuk Sohn, Giuseppe Curigliano, Ciara C. O’Sullivan, Miguel Martín, Konstantinos Tryfonidis, Libero Santarpia, Shan Yang, Veronique Dieras. Phase 3 study of tucatinib or placebo in combination with trastuzumab and pertuzumab as maintenance therapy for HER2+ metastatic breast cancer (HER2CLIMB-05, trial in progress) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT065.

Background. The development of new anti-HER2 therapies for the treatment of HER2-positive breast cancer (BC) is changing the concept of HER2 dichotomization to select and treat this patient population. In addition, different immunotherapies tested in HER2-low BC are gaining continuous interest. However, a comprehensive characterization of HER2 BC subgroups and patients is required to identify the best treatment approach. Materials and Methods. Using 123 BC samples with gene expression and IHC/FISH determined HER2 status we determined cutoff values to identify HER2 positive, HER2 low, and HER2 ultralow cohorts. With the inclusion of hormone receptor (HR) status six clinically relevant cohorts were defined (HR+/HER2+, HR+/HER2-low, HR+/HER2-ultralow, and HR-/HER2+, HR-/HER2-low, HR-/HER2-low). An ingegrated database of 7,624 BC cases were assigned to the six subtypes. Prognosis determination was based on relapse-free survival (RFS), distant-metastasis-free survival (DMFS), and overall survival (OS). Clinical parameters evaluated include MKI67 expression, lymph node status and grade. All together 17 immune signatures resembling immune genes and related activated pathways were tested against the six molecular BC subgroups. Results. We defined a robust cutoff for HER2 expression levels to define six distinct HER2 BC molecular subgroups (>3034 for HER2 positivity and < 1780 for HER2 ultralow). Regardless the HR positivity, the overall distribution of HER2-low, and HER2-ultralow was 23% and 52%, respectively. In the HR+ subgroups the HER2-low showed a better prognosis as compared to the HER2-ultralow and HER2+ (RFS and DMFS P = 0.0048 and 0.0015, respectively) while there was no prognostic effect of HER2 expression in the HR- subgroups. Not surprisingly, an association with higher grade was demonstrated in all HR- as compared to the HR+ subgroups regardless of HER2 status. Overall, all HR- subgroups showed a higher involvement of immune genes as compared to the three HR+ subgroups. Of interest, HER2-low (HR+ and HR-) and HR-/HER2+ showed a significant overlap expression of immune signatures (71%). While the HR+/HER2-ultralow and HR+/HER2+ displayed minimal activation of immune pathways, the HR-/HER2-ultralow was the group most significantly associated with the activation of immune signaling including IFN signaling (67% percent of genes in the panel with altered expression), T cell active cytokines (34% of genes hit), and cytotoxic effector molecules (48% of genes hit). Conclusions. Our study supports a further molecular stratification of breast cancer based on HER2 status. The different tumor-immune background of these BC subgroups highlights that selected patient cohorts may derive benefit from targeted immunotherapy. Citation Format: Gyongyi Munkacsy, Libero Santarpia, Balazs Gyorffy. Immune Signatures Display Subtype-Specific Activation 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 P5-02-04.

TPS1108 Background: The current first-line (1L) standard of care (SOC) for human epidermal growth factor receptor 2-positive (HER2+) metastatic breast cancer (MBC) is trastuzumab (T) plus pertuzumab (P) and a taxane. Despite advances in 1L SOC, most patients (pts) progress during maintenance therapy with T+P. Tucatinib is a tyrosine kinase inhibitor (TKI) approved in combination with T and capecitabine for adults with HER2+ MBC, with and without brain metastases (BM). In HER2CLIMB, the addition of tucatinib significantly prolonged progression-free survival (PFS) and overall survival (OS) in pts with HER2+ MBC and was well tolerated. Adding tucatinib also reduced the risk of disease progression or death in pts with untreated and/or active BM (Murthy et al. 2020, Curigliano et al. 2021). HER2CLIMB-05 investigates whether adding tucatinib to 1L SOC as maintenance therapy will extend PFS while maintaining quality of life (QOL). Methods: HER2CLIMB-05 (NCT05132582) is a phase 3, randomized, double-blind study evaluating tucatinib plus T+P as maintenance therapy for HER2+ MBC. Approximately 650 pts will be enrolled. Eligible pts will have advanced HER2+ disease, no progression on 4–8 cycles of prior 1L SOC, ECOG Performance Status of 0 or 1, and no or asymptomatic BM. Exclusion criteria include prior treatment with anti-HER2 and/or anti-epidermal growth factor receptor TKI (prior SOC for early BC is permitted) or inability to undergo contrast magnetic resonance imaging of the brain. Pts will be randomized 1:1 to receive either tucatinib or placebo twice daily, with T+P once every 21 days. Pts with HR+ disease may receive endocrine therapy. The primary endpoint is investigator-assessed PFS. Secondary endpoints include OS (key endpoint), time to deterioration of health-related QOL, central nervous system PFS, safety, and pharmacokinetic (PK) parameters. PFS and OS will be compared using a 2-sided stratified log-rank test between treatment groups. Time-to-event endpoints will be summarized using the Kaplan–Meier method. PK and safety data will be summarized using descriptive statistics. Enrollment is ongoing in the US, with additional sites planned. Clinical trial information: NCT05132582.

Background Sequence variations in coding and non-coding regions of the genome can affect gene expression and signalling pathways, which in turn may influence disease outcome. Methods In this study, we integrated somatic mutations, gene expression and clinical data from 930 breast cancer patients included in the TCGA database. Genes associated with single mutations in molecular breast cancer subtypes were identified by the Mann-Whitney U-test and their prognostic value was evaluated by Kaplan-Meier and Cox regression analyses. Results were confirmed using gene expression profiles from the Metabric data set (n = 1988) and whole-genome sequencing data from the TCGA cohort (n = 117). Results The overall mutation rate in coding and non-coding regions were significantly higher in ER-negative/HER2-negative tumours (P = 2.8E–03 and P = 2.4E–07, respectively). Recurrent sequence variations were identified in non-coding regulatory regions of several cancer-associated genes, including NBPF1, PIK3CA and TP53. After multivariate regression analysis, gene signatures associated with three coding mutations (CDH1, MAP3K1 and TP53) and two non-coding variants (CRTC3 and STAG2) in cancer-related genes predicted prognosis in ER-positive/HER2-negative tumours. Conclusions These findings demonstrate that sequence alterations influence gene expression and oncogenic pathways, possibly affecting the outcome of breast cancer patients. Our data provide potential opportunities to identify non-coding variations with functional and clinical relevance in breast cancer.

Background: The tumor immune microenvironment is formed by many distinct and interacting cell populations, and its composition may predict patient's prognosis and response to therapies. Triple negative breast cancer (TNBC) is a heterogeneous disease in which different genomic subgroups have been described (Lehmann, et al. J Clin Invest.2011). Our aim was to integrate the composition of the tumor immune microenvironment with the molecular TNBC subtypes. Methods: We retrospectively analyzed the composition and the functional orientation of the immune microenvironment of 963 TNBC tumors clustered in 4 main TNBC subgroups (Basal-Like [BL1/2], Immunomodulatory [IM], Mesenchymal/Mesenchymal Stem-Like [MS], Androgen Receptor [AR]) from independent cohorts using transcriptomic profiling. TNBC were stratified based on 9 different immune signatures (Natural Killer [NK], Dendritic Cells [DC], T-Cells [TC], B-Cells [BC], T-Cytotoxic [TC], Interferon [IF], Nuclear Factor-kB [NF-kB], anti-tumor Macrophages [M1] and pro-tumor Macrophages [M2]. We validated our findings using immunohistochemistry. Results: We report that TNBC molecular subgroups and specific microenvironmental immune signatures are highly correlated. The IM was enriched of almost all the immune modules. On overall TNBC population, the TC (P = 0.01), IF (P = 0.007) and M1 (P = 0.001) signatures were associated with good prognosis. The BL subgroup with a good prognosis was characterized by overexpression of genes specific to M1-macrophages (P = 0.004) and TC-lymphocytes (P = 0.01). In contrast, the poor-prognosis MS expresses markers of cells of monocytic origin and significantly associated with the M2 signature (P = 0.01). The MS subgroup also displays an inflammatory and immunosuppressive signature. Pathological examination revealed that the MS subtype is characterized by a high density of pro-tumor macrophages that likely produce chemokines and cytokines which favor tumor-associated inflammation, resulting in a poor prognosis. In contrast, the AR exhibits low immune and inflammatory signatures. Conclusions: The distinct immune orientations of the TNBC molecular subtypes pave the way for tailored immunotherapies. Citation Format: Bottai G, Balazs G, Nagy A, Pusztai L, Szallasi Z, Reis-Filho JS, Santarpia L. Immune signatures define and affect prognosis in triple-negative breast cancer subtypes [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 P1-07-06.

Background: Breast cancer bone metastasis (BCBM)-specific genes have been reported without considering biological differences based on estrogen receptor (ER) status. The aims of this study were to identify BCBM-specific genes using our patient dataset and validate previously reported BCBM-specific genes, and to determine whether ER-status-related biological differences matter in identification of BCBM-specific genes. Methods: We used Affymetrix GeneChips to analyze 365 primary human epidermal growth factor receptor 2 (HER2)-negative invasive breast cancer specimens. Genes that were differentially expressed between patients who developed bone metastasis and those who developed non-bone metastasis were identified using Cox proportional hazards model, and differential expression of gene sets was assessed using gene set analysis. We performed gene set analysis to determine whether biological function associated with bone metastasis were different by ER status using 2,246 functionally annotated gene sets assembled from Gene Ontology data base. Results: Among 16,712 probe sets, 592 were overexpressed in the bone metastasis cohort compared to the non-bone-metastasis cohort (false discovery rate ≤ 0.05). However, no BCBM-specific genes met our significance tests when the cancers were stratified by ER status. In ER-positive and ER-negative breast cancers, 151 and 125 gene sets, respectively, were overexpressed for BCBM and the majority of BCBM-related pathways were different. Of significant gene sets, only 13 gene sets were overlapped between ER-positive and -negative cohorts. Conclusion: ER-positive and ER-negative breast cancers have different biological pathways in BCBM development. We have yet to explore BCBM-related biomarkers and targets considering the biological features associated with BCBM depending on the ER status.

The proper validation of prognostic biomarkers is an important clinical issue in breast cancer research. MicroRNAs (miRNAs) have emerged as a new class of promising breast cancer biomarkers. In the present work, we developed an integrated online bioinformatic tool to validate the prognostic relevance of miRNAs in breast cancer. A database was set up by searching the GEO, EGA, TCGA, and PubMed repositories to identify datasets with published miRNA expression and clinical data. Kaplan–Meier survival analysis was performed to validate the prognostic value of a set of 41 previously published survival-associated miRNAs. All together 2178 samples from four independent datasets were integrated into the system including the expression of 1052 distinct human miRNAs. In addition, the web-tool allows for the selection of patients, which can be filtered by receptors status, lymph node involvement, histological grade, and treatments. The complete analysis tool can be accessed online at: www.kmplot.com/mirpower . We used this tool to analyze a large number of deregulated miRNAs associated with breast cancer features and outcome, and confirmed the prognostic value of 26 miRNAs. A significant correlation in three out of four datasets was validated only for miR-29c and miR-101. In summary, we established an integrated platform capable to mine all available miRNA data to perform a survival analysis for the identification and validation of prognostic miRNA markers in breast cancer.

UNLABELLED : Advances in DNA and RNA sequencing revealed substantially greater genomic complexity in breast cancer than simple models of a few driver mutations would suggest. Only very few, recurrent mutations or copy-number variations in cancer-causing genes have been identified. The two most common alterations in breast cancer are TP53 (affecting the majority of triple-negative breast cancers) and PIK3CA (affecting almost half of estrogen receptor-positive cancers) mutations, followed by a long tail of individually rare mutations affecting

9593 Background: The phase II multicenter, open label study, which evaluated efficacy and safety of D+T in pretreated (cohort B) and treatment (tx)-naive (cohort C) pts with BRAF V600E mut metastatic NSCLC. The results of the primary analysis have been reported. Here, we present an updated survival and genomic analysis data for cohorts B and C. Methods: Tx-naïve (n=36) and pretreated (n=57) pts received D 150 mg twice daily + T 2 mg daily. Primary objective: ORR, secondary objectives: PFS, DOR, OS, safety, tolerability and PK of D+T. Tumor samples were centrally tested using a NGS cancer targeted panel (Oncomine Dx Target test, ThermoFisher Scientific). KM curves and Cox regression models were used to evaluate potential associations between baseline genomic landscape and pt efficacy endpoints. Results: As of June 22, 2019, median (m) follow-up was 16.3 mo in tx-naïve pts and 16.6 mo in pretreated pts. mOS was 17.3 mo (95% CI: 12.3, 40.2; 3 yr OS: 40%) and 18.2 mo (95% CI: 14.3, 28.6; 3 yr OS: 33%) with 14/36 and 11/57 pts alive in tx naïve and pretreated pts respectively. Detailed efficacy results are presented in table. 57/62 tumor samples retrieved from 93 pts were centrally confirmed to have BRAF V600E mut; 5 non-confirmed BRAF tumors (3 pts had PR) were positive for c-MET T1010I, KRAS G12V, ALK fusion and 2 JAK3 S493C with mPFS of 13.8 mo while OS was NE due to limited data points. Eleven pts (18%) had concomitant somatic mutations and/or genetic alterations in addition to BRAF V600E mut: 4 had alterations within PI3K pathway4 had concomitant mutations at IDH1 R132X, and 3 pts had additional mutations at BRAF G466V, KRAS G13C and a cMET exon 14 skipping, respectively. Pts whose tumors had concomitant genetic alterations, particularly in PI3K pathway, showed a trend towards decreased PFS and OS. Safety profile was similar to previous reported results. Conclusions: This update of BRF113928 study reported improved and durable OS rates with combination D+T in BRAF V600E mut NSCLC pts. Co-occurring genetic alterations might influence clinical outcomes of such pts. Further validation is ongoing to corroborate current genomic findings. Clinical trial information: NCT01336634 . [Table: see text]

Triple-negative breast cancer (TNBC) is an aggressive subtype with no clinically proven biologically targeted treatment options. The molecular heterogeneity of TNBC and lack of high frequency driver mutations other than TP53 have hindered the development of new and effective therapies that significantly improve patient outcomes. miRNAs, global regulators of survival and proliferation pathways important in tumor development and maintenance, are becoming promising therapeutic agents. We performed miRNA-profiling studies in different TNBC subtypes to identify miRNAs that significantly contribute to disease progression. We found that miR-34a was lost in TNBC, specifically within mesenchymal and mesenchymal stem cell–like subtypes, whereas expression of miR-34a targets was significantly enriched. Furthermore, restoration of miR-34a in cell lines representing these subtypes inhibited proliferation and invasion, activated senescence, and promoted sensitivity to dasatinib by targeting the proto-oncogene c-SRC. Notably, SRC depletion in TNBC cell lines phenocopied the effects of miR-34a reintroduction, whereas SRC overexpression rescued the antitumorigenic properties mediated by miR-34a. miR-34a levels also increased when cells were treated with c-SRC inhibitors, suggesting a negative feedback exists between miR-34a and c-SRC. Moreover, miR-34a administration significantly delayed tumor growth of subcutaneously and orthotopically implanted tumors in nude mice, and was accompanied by c-SRC downregulation. Finally, we found that miR-34a and SRC levels were inversely correlated in human tumor specimens. Together, our results demonstrate that miR-34a exerts potent antitumorigenic effects in vitro and in vivo and suggests that miR-34a replacement therapy, which is currently being tested in human clinical trials, represents a promising therapeutic strategy for TNBC. Cancer Res; 76(4); 927–39. ©2015 AACR.

Patients with primary HER2-positive breast cancer benefit from HER2-targeted therapies. Nevertheless, a significant proportion of these patients die of disease progression due to mechanisms of drug resistance. MicroRNAs (miRNAs) are emerging as critical core regulators of drug resistance that act by modulating the epithelial- to-mesenchymal transition (EMT) and cancer-related immune responses. In this study, we investigated the association between the expression of a specific subset of 14 miRNAs involved in EMT processes and immune functions and the response to neoadjuvant trastuzumab and chemotherapy in 52 patients with HER2-overexpressing breast tumors. The expression of only a single miRNA, miR-21, was significantly associated with residual disease (p = 0.030) and increased after trastuzumab-chemotherapy (p = 0.012). A target prediction analysis coupled with in vitro and in vivo validations revealed that miR-21 levels inversely correlated with the expression of PTEN (rs = −0.502; p = 0.005) and PDCD4 (rs = −0.426; p = 0.019), which differentially influenced the drug sensitivity of HER2-positive breast cancer cells. However, PTEN expression was only marginally associated with residual disease. We further demonstrated that miR-21 was able to affect the response to both trastuzumab and chemotherapy, triggering an IL-6/STAT3/NF-κB-mediated signaling loop and activating the PI3K pathway. Our findings support the ability of miR-21 signaling to sustain EMT and shape the tumor immune microenvironment in HER2-positive breast cancer. Collectively, these data provide a rationale for using miR-21 expression as a biomarker to select trastuzumab-chemotherapy-resistant HER2-positive breast cancer patients who may benefit from treatments containing PI3K inhibitors or immunomodulatory drugs.

The introduction of trastuzumab for anti-HER2 therapy dramatically changed the clinical outcome for HER2 (ERBB2, neu) positive breast cancer patients. Today, patients eligible for trastuzumab are selected using HER2 expression/amplification status of the primary tumor. However, acquired and inherent resistance to anti-HER2 therapy in these patients poses a significant challenge, and better patient stratification will be needed to improve clinical response. Here, we provide a wide-ranging overview of potential biomarkers capable of stratifying patients regarding their response to trastuzumab. These include HER2 amplification, impaired access to the binding site (p95HER2, Δ16HER-2, MUC4), augmented signaling through other ERBB family receptors (HER1, HER3, HER4) and their ligands, activation of HER2 targets by alternate heterodimers (EphA2, IGF-1R, GDF15, MUC1*), signaling triggered by downstream members (PIK3CA, PTEN, SRC, mTOR), altered expression of cell cycle and apoptotic regulators (CDKs, p27(kip1), Bcl-2), hormone receptor status, resistance to antibody-dependent cellular cytotoxicity (FcγR), and altered miRNA expression signatures. Multigenic molecular profile analyses have revealed further genes not directly associated with classical oncogenic pathways. Although numerous biomarkers have shown promise in pre-clinical studies, many have delivered controversial results when evaluated in clinical trials. One of the keys for targeting ERBB2 will be to consider the entire ERBB family and downstream associated pathways responsible for the malignant transformation. The heterogeneity of the disease is likely to represent a significant obstacle to accurately predicting the course of resistance. The future most probably involves the incorporation of multiple biomarkers into a unified predictor enabling selection of patients for superior targeted drug administration.

DNA methylation has a substantial impact on gene expression, affecting the prognosis of breast cancer (BC) patients dependent on molecular subtypes. In this study, we investigated the prognostic relevance of the expression of genes reported as aberrantly methylated, and the link between gene expression and DNA methylation in BC subtypes. The prognostic value of the expression of 144 aberrantly methylated genes was evaluated in ER+/HER2−, HER2+, and ER−/HER2− molecular BC subtypes, in a meta-analysis of two large transcriptomic cohorts of BC patients (n = 1,938 and n = 1,640). The correlation between gene expression and DNA methylation in distinct gene regions was also investigated in an independent dataset of 104 BCs. Survival and Pearson correlation analyses were computed for each gene separately. The expression of 48 genes was significantly associated with BC prognosis (p

Purpose: Triple-negative breast cancers (TNBC) are associated with high risk of early tumor recurrence and poor outcome. Common prognostic biomarkers give very restricted predictive information of tumor recurrences in TNBC. Human serum contains stably expressed microRNAs (miRNAs), which have been discovered to predict prognosis in patients with cancer. The purpose of this study was to identify circulating biomarkers able to predict clinical outcome in TNBC. Experimental Design: We performed genome-wide serum miRNA expression and real-time PCR analyses to investigate the ability of miRNAs in predicting tumor relapse in serum samples from 60 primary TNBC. Patients were divided into training and testing cohorts. Results: By Cox regression analysis, we identified a four-miRNA signature (miR-18b, miR-103, miR-107, and miR-652) that predicted tumor relapse and overall survival. This miRNA signature was further validated in an independent cohort of 70 TNBC. A high-risk signature score was developed and significantly associated with tumor recurrence and reduced survival. Multivariate Cox regression models indicated that the risk score based on the four-miRNA signature was an independent prognostic classifier of patients with TNBC. Conclusions: This signature may serve as a minimally invasive predictor of tumor relapse and overall survival for patients with TNBC. This prediction model may ultimately lead to better treatment options for patients with TNBC. Clin Cancer Res; 21(5); 1207–14. ©2014 AACR.

Luminal B breast cancers (BC) have a more aggressive behavior associated with a higher rate of tumor relapse and worse prognosis compared to luminal A tumors. In this study, we evaluated the involvement of specific epithelial-to-mesenchymal transition- (EMT-) and immune-related pathways in the dissemination of luminal B BC cells. The expression of 42 EMT- and immune-related genes was evaluated in matched sentinel lymph nodes (SLNs) analyzed by the one-step nucleic acid amplification assay (OSNA) and primary tumors of 40 luminal B BC patients by gene array and immunohistochemistry. The results were validated in an independent group of 150 luminal B tumors by immunohistochemistry and immunofluorescence and using gene expression data from 315 luminal B BC patients included in the Metabric dataset. We found that the expression of CXCR4 (p=3.28E−02) and CD163 (p=6.92E−03) was significantly upregulated in SLNs of recurrent luminal B BC patients. Luminal B primary tumors overexpressing CXCR4 were characterized by an increased expression of vimentin and a high content of CD163-positive macrophages. Bioinformatics analysis confirmed the correlation of CXCR4 with CXCL12, VIM, and CD163 expression and LN involvement. Our results suggest that the upregulation of the CXCR4/CXCL12 pathway and the presence of protumor macrophages in the primary tumor and SLNs sustain the aggressiveness of an important subgroup of luminal B BC.

Breast cancers (BC) carry a complex set of gene mutations that can influence their gene expression and clinical behavior. We aimed to identify genes driven by the TP53 mutation status and assess their clinical relevance in estrogen receptor (ER)-positive and ER-negative BC, and their potential as targets for patients with TP53 mutated tumors. Separate ROC analyses of each gene expression according to TP53 mutation status were performed. The prognostic value of genes with the highest AUC were assessed in a large dataset of untreated, and neoadjuvant chemotherapy treated patients. The mitotic checkpoint gene MPS1 was the most significant gene correlated with TP53 status, and the most significant prognostic marker in all ER-positive BC datasets. MPS1 retained its prognostic value independently from the type of treatment administered. The biological functions of MPS1 were investigated in different BC cell lines. We also assessed the effects of a potent small molecule inhibitor of MPS1, SP600125, alone and in combination with chemotherapy. Consistent with the gene expression profiling and siRNA assays, the inhibition of MPS1 by SP600125 led to a reduction in cell viability and a significant increase in cell death, selectively in TP53-mutated BC cells. Furthermore, the chemical inhibition of MPS1 sensitized BC cells to conventional chemotherapy, particularly taxanes. Our results collectively demonstrate that TP53-correlated kinase MPS1, is a potential therapeutic target in BC patients with TP53 mutated tumors, and that SP600125 warrant further development in future clinical trials.

DNA repair pathways can enable tumor cells to survive DNA damage induced by chemotherapy and thus provide prognostic and/or predictive value. We evaluated Affymetrix gene expression profiles for 145 DNA repair genes in untreated breast cancer (BC) patients (n = 684) and BC patients treated with regimens containing neoadjuvant taxane/anthracycline (n = 294) or anthracycline (n = 210). We independently assessed estrogen receptor (ER)-positive/HER2-negative, HER2-positive, and ER-negative/HER2-negative subgroups for differential expression, bimodal distribution, and the prognostic and predictive value of DNA repair gene expression. Twenty-two genes were consistently overexpressed in ER-negative tumors, and five genes were overexpressed in ER-positive tumors, but no differences in expression were associated with HER2 status. In ER-positive/HER2-negative tumors, the expression of nine genes (BUB1, FANCI, MNAT1, PARP2, PCNA, POLQ, RPA3, TOP2A, and UBE2V2) was associated with poor prognosis, and the expression of one gene (ATM) was associated with good prognosis. Furthermore, the prognostic value of specific genes did not correlate with proliferation. A few genes were associated with chemotherapy response in BC subtypes and treatment-specific manner. In ER-negative/HER2-negative tumors, the MSH2, MSH6, and FAN1 (previously MTMR15) genes were associated with pathological complete response and residual invasive cancer in taxane/anthracycline-treated patients. Conversely, PMS2 expression was associated with residual invasive cancer in treatments using anthracycline as a single agent. In HER2-positive tumors, TOP2A was associated with patient response to anthracyclines but not to taxane/anthracycline regimens. In genes expressed in a bimodal fashion, RECQL4 was significantly associated with clinical outcome. In vitro studies showed that defects in RECQL4 impair homologous recombination, sensitizing BC cells to DNA-damaging agents.

Breast cancer is a heterogeneous tumor type characterized by a complex spectrum of molecular aberrations, resulting in a diverse array of malignant features and clinical outcomes. Deciphering the molecular mechanisms that fuel breast cancer development and act as determinants of aggressiveness is a primary need to improve patient management. Among other alterations, aberrant expression of microRNAs has been found in breast cancer and other human tumors, where they act as either oncogenes or tumor suppressors by virtue of their ability to finely modulate gene expression at the post-transcriptional level. In this study, we describe a new role for miR-181a/b as negative regulators of the DNA damage response in breast cancer, impacting on the expression and activity of the stress-sensor kinase ataxia telangiectasia mutated (ATM). We report that miR-181a and miR-181b were overexpressed in more aggressive breast cancers, and their expression correlates inversely with ATM levels. Moreover we demonstrate that deregulated expression of miR-181a/b determines the sensitivity of triple-negative breast cancer cells to the poly-ADP-ribose-polymerase1 (PARP1) inhibition. These evidences suggest that monitoring the expression of miR-181a/b could be helpful in tailoring more effective treatments based on inhibition of PARP1 in breast and other tumor types.

MicroRNAs (miRNAs) simultaneously modulate different oncogenic networks, establishing a dynamic system of gene expression and pathway regulation. In this study, we analyzed global miRNA and messenger RNA (mRNA) expression profiles of 17 cell lines representing different molecular breast cancer subtypes. Spearman’s rank correlation test was used to evaluate the correlation between miRNA and mRNA expression. Hierarchical clustering and pathway analysis were also performed. Publicly available gene expression profiles (n = 699) and tumor tissues (n = 80) were analyzed to assess the relevance of key miRNA-regulated pathways in human breast cancer. We identified 39 significantly deregulated miRNAs, and the integration between miRNA and mRNA data revealed the importance of immune-related pathways, particularly the Oncostatin M (OSM) signaling, associated with mesenchymal-like breast cancer cells. OSM levels correlated with genes involved in the inflammatory response, epithelial-to-mesenchymal transition (EMT), and epidermal growth factor (EGF) signaling in human estrogen receptor (ER)-negative/human epidermal growth factor receptor 2 (HER2)-negative breast cancer. Our results suggest that the deregulation of specific miRNAs may cooperatively impair immune and EMT pathways. The identification of the OSM inflammatory pathway as an important mediator of EMT in triple-negative breast cancer (TNBC) may provide a novel potential opportunity to improve therapeutic strategies.

Background and Aims: MicroRNAs (miRNAs) are short non-coding RNA whose expression levels have diagnostic and prognostic implications in cancer. However, the relevance of aberrantly expressed miRNAs to breast tumour-immune response has not been established. We aimed to assess the association between deregulated miRNAs and tumour immune response in breast molecular cancer subtypes. Methods: One hundred and seventy ductal infiltrating breast carcinomas (BC) (ER+/HER2− n=85, HER2+ n=40, ER−/HER2− n=45) were evaluated for the presence of cellular immune components by IHC assay. CD3, CD20 were used as markers for T lymphocytes infiltration (TIL), and B lymphocytes infiltration (BIL), respectively, whereas CD68 for the presence of tumour-associated macrophage (TAM). Total RNA (including miRNA) was extracted from all tumours and 32 highly specific miRNAs and 276 immune genes were evaluated by array and qRT-PCR assays. We derived an integrated immune miRNA-regulatory gene profile to tease out relationships of these genes as potential targets of specific miRNAs. In vitro experiments on BC cell lines were performed to confirm potential links between deregulated miRNAs and immune genes. Results: Lymphocytes infiltration (LI) was most common in HER2+ and ER−/HER2− BC samples (P < .004 and < .001) although B and T cells components were differently distributed in these 2 BC groups. TAM was a frequent event in ER−/HER2− BC subtype (P < .005). By gene and integration analyses we identified important miRNA immune-modulated target genes associated with prognostic factors and with molecular BC subtypes. We focused our studies on miR-181 and miR-135a that were significantly associated with ER−/HER2− (P < .001) and HER2+ BC (P < .002), respectively. BCs with abnormal expression of miR-181 and miR-135a showed an important association with distinct TIL and TAM components and specific immune genes. Importantly, preclinical data on BC cell lines demonstrated that miR-181 and miR-135a were able to regulate important cell immune-modulators such as SEMA3B and STAT6 signalling pathways, respectively. These 2 cellular pathways in turn were capable to regulate specific cascades of immune gene networks. Conclusion: We identified specific miRNAs associated with immune cellular components and immune-related tumour response in the 3 main molecular BC subtypes (ER+/HER2−, HER2+ and ER−/HER2). Aberrant expression of miR-181 and miR-135a can contribute to BC tumour immune response programs by regulating important gene targets such as SEMA3B and STAT6 signalling pathways in ER−/HER2− and HER2+ tumours, respectively. Modulation of miRNAs activating tumour immune response programs may have important implications for novel therapeutic strategies in BC. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-10-01.

Until now, no data are present in literature about the prototype Th1 chemokine (C–X–C motif) ligand 10 (CXCL10) in anaplastic thyroid cancer (ATC). This study aimed to test in “primary human ATC cells” (ANA) vs “normal thyroid follicular cells” (TFC): (a) CXCL10 secretion basally and after interferon (IFN)-γ and/or tumor necrosis factor (TNF)-α stimulation; (b) peroxisome proliferator-activated receptor (PPAR)-γ activation by thiazolidinediones, rosiglitazone or pioglitazone, on CXCL10 secretion, on proliferation and apoptosis in ANA. We demonstrate that: (a) ANA, but not TFC, produced basally CXCL10, and did so in half of cases; (b) IFN-γ stimulated dose-dependently CXCL10, in ANA and TFC; (c) TNF-α did not induce CXCL10 secretion, in ANA and TFC; (d) IFN-γ + TNF-α induced a synergistic but variable release of CXCL10 in the different ANA preparations, while it was more reproducible in TFC; (e) rosiglitazone action on CXCL10 in ANA was inhibitory in 2/6, stimulatory in 1/6 and nil in 3/6, whereas it was inhibitory in TFC; (f) rosiglitazone inhibition of proliferation in ANA was not associated with the effect on CXCL10; (g) nuclear factor-κB and ERK1/2 were basally activated in ANA, increased by IFN-γ + TNF-α, and rosiglitazone inhibited that activation. On the whole, the present data first show that ANA cells are able to produce CXCL10, basally and under the influence of cytokines. However, the pattern of modulation by IFN-γ, TNF-α or thiazolidinediones is extremely variable, suggesting that the intracellular pathways involved in the chemokine modulation in ATC have different types of deregulation.

There are no clinical tools to functionally assess degree of DNA damage in breast cancer. The comet assay is an accepted research tool for assessing DNA damage, however, most cancer studies have assessed lymphocytes as surrogate cells. The aim of this pilot study was to use the comet assay in early breast cancer directly in tumor tissue to compare DNA damage between and within traditionally defined subgroups, and to explore intra-tumoral heterogeneity. Scrapings of tumor and healthy breast tissue were obtained at primary surgery from 104 women. Comet assay was applied to quantitatively assess DNA damage, revealing substantial inter- and intra-subgroup variation. Marked intra-tumoral heterogeneity was evident across all subgroups. The degree of DNA damage for an individual could not be predicted by breast cancer subgroup. Comet assay warrants further study as a potential clinical tool for identification of tumoral DNA damage and ultimately, individualised use of DNA damaging therapy.

Introduction: The MAPK pathway comprises several key signaling components and phosphorylation events that play a role in tumorigenesis. These activated kinases transmit extracellular signals that regulate cell growth, differentiation, proliferation, apoptosis and migration functions. Alteration of the RAS–RAF–MEK–ERK–MAPK (RAS–MAPK) pathway has been reported in human cancer as a result of abnormal activation of receptor tyrosine kinases or gain-of-function mutations mainly in the RAS or RAF genes. These pathways are considered potential therapeutic targets for cancer treatment. Recently, several small-molecule inhibitors targeting this pathway have been developed and are currently being tested in clinical trials. Areas covered: The biological role of the RAS–MAPK pathway, the consequence of its disregulation and the development of small-molecule inhibitors. The rationale for targeting the RAS–MAPK pathway and the application and the results of various inhibitory molecules as anticancer agents in clinical ...

Background Used upfront or after 2 to 3 years (yrs) of tamoxifen (TAM) or as extended treatment after 5 yrs of TAM, aromatase inhibitors (AIs) are associated with less recurrences than with 5 yrs of TAM. However, up front AIs were not superior to TAM→AI sequence in node negative (N-) tumors (TEAM study, SABCS 2009; BIG1-98 trial, NEJM 2009). The observation is consistent with the hypothesis that early relapses may be more frequently due to intrinsic endocrine resistance irrespective of the use of TAM or AIs whereas late relapses depend on acquired resistance. Methods Affymetrix HGU133A-based gene expression profiles from two adjuvant datasets (n=556) of patients treated with 5 yrs TAM were evaluated and included 285 N-, 247 N+ and 24 Nx estrogen receptor-positive cases. A proliferation score based on the expression of 12 mitotic kinases (MKS) (Bianchini, Cancer Res 2010) and a 4-gene estrogen-related score (ERS) adopted from the Oncotype DX Recurrence Score were assessed. Median cut-off points were used for both biomarkers. Pattern of relapse according to marker status were evaluated in three distinct time cohorts (0–2.5 yrs, 2.5–5 yrs, 5–10 yrs). Outcome was assessed according to distant relapse rates. Results A violation of the proportional hazards assumption was found for both scores indicating time-dependent effects. The table shows distant relapse rates according to biomarker group within each time cohort. Among low proliferation tumors (lowMKS), the highERS group had low and steadily increasing recurrence rates, while the lowERS group showed a higher risk of relapse that increased continuously over the time. Among the highly proliferative tumors (highMKS), the high endocrine-sensitive group (highERS) had a lower risk of relapse within the 0–2.5 yrs compared to lowERS cancers. The difference is not persisting at the longer follow up of 2.5–5 yrs, and at 5–10 yrs the highERS group has higher risk of relapse. The pattern of relapse was similar for N- and N+ cancers. However, in the 0–2.5 yrs interval all recurrences occurred in the highMKS/lowERS among N- cancers, while only 57% of recurrences did occur in N+ cases in the same biomarkers group (p=0.012). Discussion Highly proliferative, high endocrine-sensitive (highERS) cancers are at the greatest risk of late relapse and extended endocrine therapy beyond 5 yrs may be useful. Low proliferation, low ERS cancers also remain at substantial risk for late recurrences. Between 0 to 2.5 yrs all recurrences in N- tumors and close to 60% in N+ were in high proliferative/low endocrine-sensitive tumors. This difference could explain the beneficial trend for up-front AIs vs. sequential TAM→AIs in the N+, but not in N- subgroups of the TEAM and BIG1-98 trials. It also is consistent with the hypothesis that the highly proliferative low ERS group includes tumors intrinsically resistant to both AIs and TAM. Risk stratification by these two simple metrics may improve the readout of future adjuvant clinical trials with endocrine drugs, and may influence their design. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr S1-7.

Background: Bone metastasis-specific genes in breast cancer have been reported without considering the significant differences in ER status between bone and non-bone metastases. The aims of this study were to validate genes that had been reported as bone metastasis-specific genes using our data set and to identify bone metastasis-specific genes on the basis of biological differences between ERpositive and ER-negative breast cancers. Patients and Methods: We used Affymetrix GeneChip arrays to analyze tumor samples obtained from 365 primary invasive breast cancer patients who underwent surgery from 1999 to 2008. We excluded patients with HER2−positive breast cancer (normalized HER2 mRNA expression [probe set 216836_s_at] > 12.54). We classified the samples into 3 cohorts according to first metastatic site: bone, non-bone, or no metastasis. Differential expression of genes between bone and non-bone cohorts that were differentially expressed was identified using the Cox proportional hazards model, and gene sets was assessed using gene-set analysis. Results: Of the 365 patients, 34 (9.3%) were included in the bone cohort and 32 (8.8%) in the non-bone cohort. Two hundred fourteen (58.6%) had ER-positive and 151 (41.4%) had ER-negative breast cancer. First, we performed gene-set analysis using 5 gene sets that had been reported to be associated with bone metastasis. One gene set, which had been detected using an ER-negative breast cancer cell line, was validated as predicting bone metastasis in ER-positive breast cancer. None of the 5 gene sets predicted bone metastasis in ER-negative breast cancer. We then determined the levels of individual genes associated with bone metastasis by ER status using all 16,712 probe sets filtered by average gene expression level. When we analyzed all patients without any stratification by ER status, as in previous studies, 592 probe sets were significantly overexpressed in the bone cohort compared with the non-bone cohort, with a false discovery rate of ≤0.05. However, when we analyzed ER-positive and ER-negative breast cancers separately, no genes were found with significant differences between bone and non-bone cohorts. Finally, we used 2,246 functionally annotated gene sets assembled from Gene Ontology to examine possible biological differences between bone and non-bone cohorts. In the bone cohort, 151 and 125 gene sets were significantly overexpressed in ER-positive and ER-negative breast cancers, respectively (P ≤ 0.05). Ppathways related to Cellular growth and proliferation, and intracellular and second-messenger signaling were overexpressed in ER-positive breast cancer, whereas pathways related to nuclear receptor and cytokine signaling were overexpressed in ER-negative breast cancer. Most bone-metastasis-related pathways were different in ER-positive and ER-negative breast cancers (91.4% and 89.6% of the gene sets, respectively). Discussion: No genes were found that can predict bone metastasis. ER-positive and ER-negative breast cancers have different biological potentials for bone metastasis. Therefore, we need to assess the prediction model of bone metastasis based on the biological features for each ER status separately. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-16-02.

BACKGROUND Trastuzumab is part of the standard treatment for HER-2 positive breast cancer patients, but not all patients respond to trastuzumab. Altered expression levels for microRNAs in cancer cells have been correlated with prognosis and response to chemotherapy. We hypothesized that altered expression levels for miRNAs in plasma are associated with sensitivity to trastuzumab in patients with HER-2 positive breast cancer.

The past decade has seen extensive research into potential markers of responsiveness to anthracycline therapy in breast cancer patients; however, such markers have remained elusive. The status of both human epidermal growth factor receptor-2 (HER2) and topoisomerase II alpha (TOP2A) genes has been investigated in this context, but neither can be considered a clinically reliable predictor of response to anthracyclines. Expression of the TOP2A protein is affected by a number of factors not always related to gene copy number, and these might provide future potential markers. Recent studies have suggested that stroma-related signatures could predict anthracycline resistance, and increased expression of tissue inhibitor of metalloproteinases 1 (TIMP1) has also been implicated in resistance. Deficiency of the BRCA1 and BRCA2 genes may render cells more sensitive to topoisomerase inhibitors such as anthracyclines by disrupting repair of damaged DNA. Chromosome 17 polysomy has also been associated with increased responsiveness to anthracyclines. Given the complexity of topoisomerases and DNA repair pathways, it may be that a multifactorial approach, rather than reliance on a single biomarker, is needed to identify anthracycline-sensitive patients.

Fulvestrant is a pure estrogen antagonist that binds, blocks and downgrades the estrogen receptor (ER). Its unique mechanism of action is its antitumor activity after progression on prior endocrine therapy. Fulvestrant has shown activity in ER-dependent cells that are ligand independent. Fulvestrant has been approved at 250 mg/month for postmenopausal women with hormone-sensitive advanced breast cancer after progression or recurrence on antiestrogen therapy. The fulvestrant 500 mg regimen has just received approval by the EMA and the US FDA, supported by dose-dependent ER downregulation and the recent results of the clinical trial CONFIRM. Fulvestrant in combination with systemic lowering of estrogen has shown no improvement over fulvestrant alone. Combination therapy with inhibitors of growth factor signaling may have greater efficacy and is under exploration. To enhance the benefit of fulvestrant and improve outcomes for individuals with ER-positive breast cancer, greater understanding of resistance mechanisms is required. A key issue is identification of patients with ER-positive disease who retain sensitivity to antiestrogen therapy after progression on tamoxifen and/or aromatase inhibitors.

Methyl 2-cyano-3,11-dioxo-18β-olean-1,12-dien-30-oate (CDODA-Me) and the corresponding 2-trifluoromethyl analog (CF(3)DODA-Me) are derived synthetically from the triterpenoid glycyrrhetinic acid, a major component of licorice. CDODA-Me and CF(3)DODA-Me inhibited growth of highly invasive ARO, DRO, K-18, and HTh-74 thyroid cancer cells and this was due, in part, to decreased expression of specificity protein (Sp) transcription factors Sp1, Sp3, and Sp4 that are overexpressed in these cells. CDODA-Me and CF(3)DODA-Me also decreased expression of Sp-dependent genes, such as survivin and vascular endothelial growth factor (VEGF), and induced apoptosis. In addition, pituitary tumor-transforming gene-1 (PTTG-1) protein and mRNA levels were also decreased in thyroid cancer cells treated with CDODA-Me or CF(3)DODA-Me and this was accompanied by decreased expression of PTTG-1-dependent c-Myc and fibroblast growth factor-2 (FGF-2) genes. RNA interference studies against Sp1, Sp3, and Sp4 proteins showed that in thyroid cancer cells, PTTG-1 was an Sp-dependent gene. This study demonstrates for the first time that drugs, such as CDODA-Me and CF(3)DODA-Me, that decrease Sp protein expression also downregulate PTTG-1 in thyroid cancer cells and therefore have potential for clinical treatment of thyroid cancer and other endocrine neoplasias where PTTG-1 is a major pro-oncogenic factor.

With increased use of aromatase inhibitors (AIs) in the adjuvant and first-line metastatic settings for postmenopausal women with estrogen receptor (ER)-positive breast cancer, systemic relapse or progressive metastatic disease on AIs is an increasingly encountered clinical scenario. Overcoming resistance is a priority. Patients with AI-resistant disease represent a heterogeneous population, with diverse mechanisms of resistance dictating varied sensitivity to subsequent treatment. Cells with persistent dependence on ER signaling may be inhibited by fulvestrant, in which case dose-dependent ER downregulation and activity favor high-dose, loading schedule fulvestrant. In direct contrast, cells with long-term estrogen deprivation with adaptive estrogen hypersensitivity may be inhibited by exposure to estrogen. Cell survival by alternate growth signaling pathways may be inhibited by targeted agents. Currently missing, however, are predictive biomarkers to identify underlying resistance mechanisms and guide effective post-AI therapy for individual patients.

Activation of tyrosine kinase receptors (TKRs) and their related pathways has been associated with development of endocrine tumors. Compounds that target and inactivate the kinase function of these receptors, tyrosine kinase inhibitors (TKIs), are now being applied to the treatment of endocrine tumors. Recent clinical trials of TKIs in patients with advanced thyroid cancer, islet cell carcinoma, and carcinoid have shown promising preliminary results. Significant reductions in tumor size have been described in medullary and papillary thyroid carcinoma, although no complete responses have been reported. Case reports have described significant tumor volume reductions of malignant pheochromocytomas and paragangliomas. In addition, these compounds showed an initial tumoricidal or apoptotic response followed by long-term static effects on tumor growth. Despite the promising preliminary results, this class of therapeutic agents has a broad spectrum of adverse effects, mediated by inhibition of kinase activities in normal tissues. These adverse effects will have to be balanced with their benefit in clinical use. New strategies will have to be applied in clinical research to achieve optimal benefits. In this review, we will address the genetic alterations of TKRs, the rationale for utilizing TKIs for endocrine tumors, and current information on tumor and patient responses to specific TKIs. We will also discuss the adverse effects related to TKI treatment and the mechanisms involved. Finally, we will summarize the challenges associated with use of this class of compounds and potential solutions.

Von Hippel Lindau disease is a common cause of apparently sporadic pheochromocytomas. Herein, we describe a 20-year-old man with an apparently sporadic pheochromocytoma associated with a novel, relatively conservative germline Gly104Val VHL gene mutation, which is localized within exon 1 of the VHL gene corresponding to the beta -domain of the VHL protein (pVHL). The nearly asymptomatic patient's father also carries the same mutation. Similar to other mutations localized in the same codon, the Gly104Val VHL mutation seems to have an attenuated disease phenotype.

Circulating nucleic acids such as DNA and microRNA are released and circulate in the blood of cancer patients. In breast cancer, free circulating nucleic acids are being explored as potential blood biomarkers for real-time tumor monitoring. In the past decades, increasing evidence has emerged indicating potential use of circulating DNA for assessment of tumor burden and for tumor genomic and epigenetic profiling. MicroRNA profiling studies also suggest potential utility for breast cancer screening, prognosis evaluation and interrogating mechanisms of therapy resistance and tumor biology. However, a variety of preanalytical considerations must be contemplated and ultimately clinical validity and utility must be demonstrated. This book chapter will explore the main methods to detect and analyze circulating tumor DNA and circulating microRNA, and the clinical applications for circulating free nucleic acids analysis in breast cancer.

MicroRNAs (miRNAs) comprise a class of small endogenous non-coding RNA molecules that play critical roles in modulating numerous biological pathways by regulating gene expression. High throughput and expression profile studies have shown that miRNAs are commonly dysregulated in human cancer. The study of the mechanisms of action of miRNAs has uncovered an entirely new repertoire of potential biomarkers and generegulated pathways. MiRNAs may function as oncogenes or tumour suppressor genes and are characterised by unique properties such as stability, tissue specificity, ease of detection and manipulation. Additionally, miRNAs are differentially expressed in the blood of cancer patients versus healthy donors, providing a rationale for the detection of miRNAs as diagnostic and prognostic circulating biomarkers. Recent studies have shown that specific expression patterns of miRNAs could be used as potential predictors of response to treatments in clinical trials. Finally, manipulation of miRNA expression in cancer could be used for future molecular therapies.

1096 Background: Triple-negative breast cancer (TNBC) is generally characterized by high levels of chromosomal instability (CIN) and an intense immune infiltration. However, the link between these two hallmarks and its implications for clinical practice has not been fully elucidated. Methods: We generated eight immune metagenes representing various immune components: natural killer [NK], dendritic cells [DC], T-cells [TC], B-cells [BC], cytotoxic T-cells [CT], interferon [IFN], nuclear factor-κB [NF-kB], and macrophages [M]. Publicly available gene expression data from forty-two data sets, including 862 TNBC samples, were collected. TNBC tumors were clustered in three main subgroups (Basal-Like [BL1/2], Immunomodulatory [IM], and Mesenchymal/Mesenchymal Stem-Like [MS]) using transcriptomic profiling. The CIN70 signature was used to stratify TNBC patients according to the levels of CIN. Statistical analyses were performed using Mann–Whitney U test and Kaplan-Meier analyses. Results: The majority of TNBC samples showed a high level of CIN (83%), and several immune modules were differentially expressed between CIN-high and CIN-low tumors. Specifically, CT, NK, DC, M, and NF-kB signatures were overexpressed in CIN-low TNBC ( p < 1.0E-04). We then evaluated the distribution of genomic instability among TNBC molecular subgroups. Noteworthy, the CIN-high group was composed by a comparable proportion of BL1/2 (39%) and MS (35%) tumors, while CIN-low TNBCs were consistently enriched for MS cancers (61%). Higher expression of the NK, M, and IFN metagenes lead to better survival in CIN-high tumors ( p = 1.9E-02, p = 2.1E-04, and p = 1.1E-03, respectively). Only IFN had the same correlation to survival in CIN-low ( p = 1.4E-02). Conclusions: TNBCs with low levels of CIN may principally enclose M/MSL tumors, which are characterized by an intense immune infiltration and overall good prognosis. Conversely, the TNBC CIN-high group is more heterogeneous in terms of both biological features and levels of immune infiltrates. Therapeutic strategies to promote and boost immune response in the genomically unstable TNBC subgroup warrant further investigation.

MicroRNAs (miRNAs) represent a class of small, non-coding RNAs that control gene expression by targeting mRNA and triggering either translational repression or RNA degradation. The objective of our study was to evaluate the involvement of miRNAs in human medullary thyroid carcinoma (MTC) and to identify the markers of metastatic cells and aggressive tumour behaviour. Using matched primary and metastatic tumour samples, we identified a subset of miRNAs aberrantly regulated in metastatic MTC. Deregulated miRNAs were confirmed by quantitative real-time PCR and validated by in situ hybridisation on a large independent set of primary and metastatic MTC samples. Our results uncovered ten miRNAs that were significantly expressed and deregulated in metastatic tumours: miR-10a, miR-200b/-200c, miR-7 and miR-29c were down-regulated and miR-130a, miR-138, miR-193a-3p, miR-373 and miR-498 were up-regulated. Bioinformatic approaches revealed potential miRNA targets and signals involved in metastatic MTC pathways. Migration, proliferation and invasion assays were performed in cell lines treated with miR-200 antagomirs to ascertain a direct role for this miRNA in MTC tumourigenesis. We show that the members of miR-200 family regulate the expression of E-cadherin by directly targeting ZEB1 and ZEB2 mRNA and through the enhanced expression of tumour growth factor β (TGFβ)-2 and TGFβ-1. Overall, the treated cells shifted to a mesenchymal phenotype, thereby acquiring an aggressive phenotype with increased motility and invasion. Our data identify a robust miRNA signature associated with metastatic MTC and distinct biological processes, e.g., TGFβ signalling pathway, providing new potential insights into the mechanisms of MTC metastasis.

Parafollicular C-cell-derived medullary thyroid cancer (MTC) comprises 3% to 4% of all thyroid cancers. While cytotoxic treatments have been shown to have limited efficacy, targeted molecular therapies that inhibit rearranged during transfection (RET) and other tyrosine kinase receptors that are mainly involved in angiogenesis have shown great promise in the treatment of metastatic or locally advanced MTC. Multi-tyrosine kinase inhibitors such as vandetanib, which is already approved for the treatment of progressive MTC, and cabozantinib have shown distinct advantages with regard to rates of disease response and control. However, these types of tyrosine kinase inhibitor compounds are able to concurrently block several types of targets, which limits the understanding of RET as a specific target. Moreover, important resistances to tyrosine kinase inhibitors can occur, which limit the long-term efficacy of these treatments. Deregulated cellular signaling pathways and genetic alterations in MTC, particularly the activation of the RAS/mammalian target of rapamycin (mTOR) cascades and RET crosstalk signaling, are now emerging as novel and potentially promising therapeutic treatments for aggressive MTC.

The presence of tumor-infiltrating lymphocytes (TILs) is a prognostic factor in triple-negative breast cancer (TNBC). Specifically, cytotoxic CD8+ cells are associated with favorable outcome in TNBC. Recently, the integrin CD103 has been suggested as a potential prognostic marker in breast cancer. In this study, we aimed to evaluate the functional status and clinical relevance of CD8+ and CD103+ TILs in TNBC. A retrospective cohort of 210 formalin-fixed, paraffin-embedded tissues from patients with primary invasive ductal TNBC was assessed for the presence of CD8, CD103 and the checkpoint receptor PD-1 by immunohistochemistry assay. Whole tumor slides were assessed. Cases where ≥5% of TILs expressed CD103 or PD-1 were considered positive. Statistical analyses were performed using Spearman's correlation, Kaplan-Meier and Cox regression analyses. We found that CD103+ cells mostly co-expressed the CD8 marker, and were preferentially distributed within tumor epithelium. No consistent correlation was found between the presence of CD103+ lymphocytes and the expression of its ligand E-cadherin by TNBC cells (rs = 0.365). CD8+ lymphocytes were consistently associated with better relapse-free survival (RFS) and overall survival (OS) in both univariate (HR = 0.61; P = 1.06E-02 for RFS; HR = 0.59; P = 1.93E-02 for OS) and multivariate analysis (HR = 0.65; P = 2.45E-02 for RFS; HR = 0.63; P = 3.96E-02 for OS). The presence of CD103+ lymphocytes significantly correlated with prolonged RFS and OS in univariate analysis only (HR = 0.82; P = 4.12E-02 for RFS; HR = 0.85; P = 4.93E-02 for OS), and a trend for longer RFS was also observed in univariate analysis for PD-1 (HR = 0.71; P = 5.22E-02). Interestingly, a subset of TNBC showed co-expression of CD103+/PD-1+ in lymphocytes localized to the intraepithelial areas of the tumor. The expression of CD103 on CD8+ T cells in direct contact with cancer cells may identify a subpopulation of cells with potent cytolytic activity. The interaction between CD103+ cytotoxic lymphocytes and TNBC cells is mediated by different mechanisms rather than the binding to E-cadherin. Even though CD103 has a role in mediating an effective anti-tumor immune response, its presence alone may not be sufficient to impact the outcome of TNBC patients. Immunomodulatory therapies may be useful to boost the anti-tumor activity of potentially quiescent CD103+/PD-1+ cells in a subgroup of TNBC patients. Citation Format: Giulia Bottai, Massimo Roncalli, Libero Santarpia. CD103+/PD-1+ T-cells identify a subset of triple-negative breast cancer eligible for targeted checkpoint inhibition [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A118.

Background. MicroRNAs (miRNAs) are small non-coding RNAs capable of simultaneously regulating multiple gene networks, and affecting breast cancer patients’ outcome. Here we present the development of an online tool for the real-time meta-analysis of published miRNA datasets to identify novel prognostic biomarkers in breast cancer. Methods. First, a comprehensive database was set up by searching GEO, TCGA, and PubMed repositories to identify datasets with published miRNA expression and clinical data. Due to platform differences, each dataset was processed separately. Kaplan-Meier and Cox regression analyses were performed to investigate the prognostic value of a set of dysregulated miRNAs in breast cancer. The complete analysis tool can be accessed online at: www.kmplot.com/mirna. Results. Overall, 2,061 samples from four independent datasets were integrated into the tool including the expression signature of 1,302 distinct miRNAs. In addition to overall survival data, ER status (n = 2,039), histological grade (n = 1,396) and lymph node status (n = 1,933) are also available. By using our online tool, we demonstrated the prognostic value of some of the previous reported miRNAs implicated in breast cancer. For instance, miR-29c, miR-34c, miR-101, miR-125, and miR-190b, showed a consistent prognostic value in at least three out of four breast cancer datasets. Discussion. In summary, we established the first online integrated platform for the rapid identification of the prognostic value of miRNAs in breast cancer. Citation Format: Balázs Győrffy, András Lánczky, Giulia Bottai, Ádám Nagy, András Szabó, Libero Santarpia. Developing an online tool to validate survival-associated miRNAs utilizing expression data from 2,061 breast cancer 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 1958.

11562Background: Mammography is the standard for breast cancer (BC) screening and diagnosis. However, its limited accuracy and false-positive results necessitate the identification of novel complem...

Triple-negative breast tumours are defined as oestrogen receptor (ER)-negative, progesterone receptor (PgR)-negative and human epidermal growth factor receptor 2 (HER2)-negative. Beyond this common negative triplet, however, triple-negative breast cancers (TNBC) are not an homogeneous subgroup. There is substantial intra-subgroup diversity in tumour biology, prognosis and treatment sensitivity. Triple-negative breast cancer accounts for 15−20% of all breast cancer cases; however, it accounts for a disproportionate number of breast cancer relapses and deaths. Studies in early breast cancer have shown patients with TNBC to have a worse outcome compared with patients with non-TNBC [1]. Interestingly, neo-adjuvant studies highlight a subgroup of TNBC patients, approximately 20%, with highly chemosensitive disease and post-chemotherapy outcomes as favourable as their non-TNBC counterparts [2]. A key issue with TNBC is the accurate diagnosis of histological subtype and ER, PgR and HER2 status. ER, PgR and HER2 measurement has been associated with concerns regarding reliability and reproducibility, with remarkable reported rates of discordance. Furthermore, prior arbitrary thresholds for defining positivity for ER and PgR status, including 1%, 10% and 20%, have varied between laboratories and clinical trials. Clarity is offered by recent St Gallen and ASCO-CAP guidelines that define endocrine responsiveness as 1%. TNBC includes several morphological subtypes. Most are high-grade ductal carcinomas (not otherwise specified) but the triple-negative phenotype also occurs in medullary, apocrine and squamous cell carcinomas. Some subtypes, such as medullary carcinoma, are associated with a better prognosis and may not require aggressive chemotherapy. In contrast to endocrine-sensitive and HER2-positive breast cancers, which are defined by the presence of specific targets for matched targeted therapy, there is currently no targeted therapy for TNBC. There are promising new targeted biological therapies, such as PARP inhibitors; however, chemotherapy remains the mainstay of systemic therapy for TNBC. The biological diversity displayed within TNBC does not support such an empirical approach; however, a lack of robust predictive biomarkers prevents a more individualised approach to the choice of adjuvant therapy. Predictive markers could guide chemotherapy use by identification of the subset of TNBC patients with chemosensitive disease, or more specifically to predict sensitivity or resistance to individual chemotherapeutic agents. However, currently there are no clinical tools to recommend use, or omission, of specific chemotherapeutics. Conventional thirdgeneration combination chemotherapy is the standard treatment. Rates of pathological complete response to conventional neoadjuvant anthracycline/taxane-based chemotherapy are reported to be within the range of 13−45% [2]. Optimal adjuvant systemic therapy for TNBC is difficult to define because of a lack of robust prospective data in triple-negative restricted trial populations. Most clinical data derive from retrospective exploratory subgroup analyses from biologically unselected trial populations, and small underpowered studies. Most data reveal a highly chemosensitive TNBC subset. Lack of randomised phase III trials with a standard therapy control arm make it difficult to determine whether this increased sensitivity is agent-specific or whether it reflects general sensitivity to chemotherapy (Fig. 1). Triple-negative breast cancers are associated with a high proliferative rate, which may render them particularly sensitive to chemotherapy. Furthermore, a subset of TNBCs displays phenotypic overlap with BRCA1-mutation-related breast cancers. BRCA1 is critical in homologous recombination, a cellular process of double-strand DNA damage repair, and in the cell cycle arrest necessary for DNA repair.

We hypothesized that distinct biological processes might be associated with prognosis and chemotherapy sensitivity in the different types of breast cancers.We performed gene set analyses with BRB-ArrayTools statistical software including 2331 functionally annotated gene sets (ie, lists of genes that correspond to a particular biological pathway or biochemical function) assembled from Ingenuity Pathway Analysis and Gene Ontology databases corresponding to almost all known biological processes. Gene set analysis was performed on gene expression data from three cohorts of 234, 170, and 175 patients with HER2-normal lymph node-negative breast cancer who received no systemic adjuvant therapy to identify gene sets associated prognosis and three additional cohorts of 198, 85, and 62 patients with HER2-normal stage I-III breast cancer who received preoperative chemotherapy to identify gene sets associated with pathological complete response to therapy. These analyses were performed separately for estrogen receptor (ER)-positive and ER-negative breast cancers. Interaction between gene sets and survival and treatment response by breast cancer subtype was assessed in individual datasets and also in pooled datasets. Statistical significance was estimated with permutation test. All statistical tests were two-sided.For ER-positive cancers, from 370 to 434 gene sets were associated with prognosis (P ≤ .05) and from 209 to 267 gene sets were associated with chemotherapy response in analysis by individual dataset. For ER-positive cancers, 131 gene sets were associated with prognosis and 69 were associated with pathological complete response (P ≤.001) in pooled analysis. Increased expression of cell cycle-related gene sets was associated with poor prognosis, and B-cell immunity-related gene sets were associated with good prognosis. For ER-negative cancers, from 175 to 288 gene sets were associated with prognosis and from 212 to 285 gene sets were associated with chemotherapy response. In pooled analyses of ER-negative cancers, 14 gene sets were associated with prognosis and 23 were associated with response. Gene sets involved in sphingolipid and glycolipid metabolism were associated with better prognosis and those involved in base excision repair, cell aging, and spindle microtubule regulation were associated with chemotherapy response.Different biological processes were associated with prognosis and chemotherapy response in ER-positive and ER-negative breast cancers.

Different kinases are expressed in different clinical subsets of breast cancer. In this study, we assessed kinase expression patterns in different clinical subtypes of breast cancer, evaluated the prognostic and predictive values of kinase metagenes, and investigated their functions in vitro. Four hundred twenty-eight protein kinases in gene expression data were examined from 684 cases of breast cancer and 51 breast cancer cell lines to identify kinase expression patterns. We tested the prognostic value of kinase metagenes in 684 node-negative patients who received no adjuvant therapy and the predictive value in 233 patients who received uniform neoadjuvant chemotherapy. Twelve kinases were overexpressed in estrogen receptor (ER)–positive/human epidermal growth factor receptor 2 (HER2)–negative, 7 in HER2+, and 28 in ER−/HER2− cancers, respectively. We examined the functional role of 22 kinases overexpressed in ER−/HER2− cancers using siRNA. Downregulation of these kinases caused significant subtype-specific inhibition of cell growth in vitro. Two robust kinase clusters, including an immune kinase cluster and a mitosis kinase cluster, were present in all clinical subgroups. High mitosis kinase score was associated with worse prognosis but higher pathologic complete response (pCR) in ER+/HER2− cancers, but not in ER−/HER2− or HER2+ cancers, in univariate and multivariate analyses including other genomic predictors (MammaPrint, genomic grade index, and the 76-gene signature). Conversely, higher immune kinase score was associated with better survival in ER+/HER2− and HER2+ tumors and also predicted higher probability of pCR in HER2+ cancers. Taken together, our results indicate that kinases regulating mitosis and immune functions convey distinct prognostic information that varies by clinical subtype. Cancer Res; 70(21); 8852–62. ©2010 AACR.

BACKGROUND: The follicular variant of papillary thyroid carcinoma (FVPTC) is the second most common histotype among papillary thyroid cancers (PTCs). Although the prognosis of FVPTC is similar to the conventional phenotype, differential diagnostic difficulties may not be uncommon with other follicular thyroid neoplasms, and little is known about their genetic alterations. Defining these alterations may lead to the identification of diagnostic and biologic markers. METHODS: In this study, the authors evaluated genetic alterations and downstream-activated signals of the Ras/Raf–mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K)/v-akt murine thymoma viral oncogene (Akt) (PI3K/Akt) signaling pathways in 30 FVPTC tissue specimens. Tumors and matched normal thyroid samples were tested for RAS, for the v-raf murine sarcoma viral oncogene (BRAF) substitution of valine (V) for glutamate (E) at codon 600 (the V600E mutation), for phosphatase and tensin homolog (PTEN), for catalytic PI3k p110 subunit alpha (PIK3CA), for AKT, and for the presence of rearranged during transfection (ret) proto-oncogene/PTC (RET-PTC) and paired box-8 (PAX8)/peroxisome proliferator-activated receptor γ (PPARγ) fusion protein (PAX8-PPARγ) rearrangements by direct sequencing and reverse transcriptase-polymerases chain reaction analyses, respectively. Western blot analysis was used to assess the effects of these gene abnormalities on the activation of the 2 pathways. RESULTS: Genetic alterations were identified in 70% of FVPTCs. Activation of the MAPK and PI3K pathways was observed in 74% and 22% of tumors, respectively. The alterations that were identified in the genes of the 2 pathways were mutually exclusive. Chromosomal RET-PTC and PAX8-PPARγ rearrangements were observed in 20% and 17% of tumors, respectively. It was noteworthy that some FVPTCs with RET-PTC had the coactivation of both pathways. CONCLUSIONS: RET-PTC and PAX8-PPARγ rearrangements and mutations of the neuroblastoma RAS viral oncogene homolog N-RAS at codon 61 were the most common genetic alterations in FVPTCs. Activation of the MAPK pathway was a frequent event in FVPTCs, and the PI3K signaling pathway could be coactivated in RET-PTC tumors. These findings may have important therapeutic implication in patients with FVPTC. Cancer 2010. © 2010 American Cancer Society.

Several lines of evidence indicate that tumorigenesis is a complex multistep process, and that most, if not all, cancers acquire the same set of functional capabilities during development and progression, albeit through various mechanistic strategies. Increasing data show an important role of microRNAs (miRNAs or miRs) in regulating various aspects of cancer biology. This review describes the role of microRNAs during the multiple steps that drive the progressive transformation of normal cells into highly malignant derivatives, outlining the role of microRNAs in regulating the common hallmarks of tumorigenesis: self-sufficiency in growth signals, insensitivity to antigrowth signals, abnormal apoptosis, limitless replicative potential, induction and sustained angiogenesis, and tissue invasion and metastasis. Recent evidence suggests an important role of microRNAs in the regulation of the expression of most genes regulating and coordinating a wide variety of processes in endocrine glands. We will highlight microRNAs of potential relevance to endocrine tumors and hormone-dependent cancers. Through this overview of how microRNAs regulate multiple targets and entire pathways, we will provide insight into the potential to develop new molecular microRNA-targeted therapies for endocrine tumors.

To assess the mutational status of BRAF in FVPTC, we directly sequenced the genomic DNA of 30 primary FVPTC samples. BRAF mutations were found in only 4 (13%) tumors. We also identified a previously unknown (novel) mutation in the activation kinase domain of the BRAF (A598V), replacing alanine with valine. Functional analysis showed that this mutation led to the up-regulation of the BRAF kinase activity and its downstream signaling factors. The effect of this mutation on the structural formation of the protein is highlighted. Our results confirm the infrequency of BRAF (V600E) mutation in FVPTC and identify a novel (A598V) mutation of this gene.

Background: The prognostic effects of somatic gene mutations and correlated gene expression in breast cancer is argument of debate. In this study we analyzed the impact of specific mutations on gene expression and their relevance in the prognosis of breast cancer subtypes. Materials and methods: Exome sequencing and RNA-seq data obtained from TCGA were analyzed. Data was processed using MuTect, MapSplice and RSEM. All together data from 757 patients (ER-/HER2- [n=143], HER2+ including ER positive and negative patients, [n=136], and ER+/HER2- [n=478]) were included. Univariate Receiver Operating Characteristic (ROC) analysis was performed for the top mutated genes (mutated in at least 5% of patients) using the ROC Bioconductor library in R to identify genes whose expression was significantly associated with a mutation. Then, the mean expression of the significant genes was designated as a metagene for each genotype. We assessed the correlation with survival for each metagene by Cox proportional hazards regression and by plotting Kaplan-Meier survival plots. A significance threshold of p Results: In the overall population only few mutated genes including TP53 (HR=1.66), CDH1 (HR=0.61), AKT1 (HR=0.54), ATM (HR=1.76), NF1 (HR=0.58), KMT2D (HR=2.32), and UBR5 (HR=1.94) were significantly associated with survival. In ER-/HER2- mutant samples the PIK3CA (HR=2.79) and MAP3K1 (HR=2.98), and in HER2+ mutant samples the ARID1A (HR=0.26) and PIK3CA (HR=0.27) metagenes were associated with survival, respectively. Overall, using the combined metagene the majority of the significant mutated genes retained their prognostic power. Mutations of specific genes impacted their own expression and prognosis. The expression of TP53 (AUC=0.609, p=2.60E-06), and MAP3K1 (AUC=0.617, p=6.07E-03) was higher in samples with a mutation while the expression of CDH1 (AUC=0.684, p=2.72E-07), PTEN (AUC=0.687, p=1.47E-04), and BRCA1 (AUC=0.608, p=2.24E-02) was lower. Conclusions: Our finding support that specific mutated genes may differentially impact prognosis in breast cancer subtypes. Further efforts are required to understand the biological and prognostic role of specific activating and inactivating mutations across molecular breast cancer subtypes. Citation Format: Gyorffy B, Pongor L, Szabo A, Bottai G, Pusztai L, Santarpia L. Somatic mutation patterns differentially affect survival in breast cancer molecular subtypes. [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 PD6-06.