6533b853fe1ef96bd12ac291

RESEARCH PRODUCT

Triple negative breast cancer subtypes and pathologic complete response rate to neoadjuvant chemotherapy.

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description

Triple negative breast cancer (TNBC) is a heterogeneous disease with distinct molecular subtypes that differentially respond to chemotherapy and targeted agents. The purpose of this study is to explore the clinical relevance of Lehmann TNBC subtypes by identifying any differences in response to neoadjuvant chemotherapy among them. We determined Lehmann subtypes by gene expression profiling in paraffined pre-treatment tumor biopsies from 125 TNBC patients treated with neoadjuvant anthracyclines and/or taxanes +/- carboplatin. We explored the clinicopathological characteristics of Lehmann subtypes and their association with the pathologic complete response (pCR) to different treatments. The global pCR rate was 37%, and it was unevenly distributed within Lehmann's subtypes. Basal-like 1 (BL1) tumors exhibited the highest pCR to carboplatin containing regimens (80% vs 23%, p=0.027) and were the most proliferative (Ki-67>50% of 88.2% vs. 63.7%, p=0.02). Luminal-androgen receptor (LAR) patients achieved the lowest pCR to all treatments (14.3% vs 42.7%, p=0.045 when excluding mesenchymal stem-like (MSL) samples) and were the group with the lowest proliferation (Ki-67≤50% of 71% vs 27%, p=0.002). In our cohort, only tumors with LAR phenotype presented non-basal-like intrinsic subtypes (HER2-enriched and luminal A). TNBC patients present tumors with a high genetic diversity ranging from highly proliferative tumors, likely responsive to platinum-based therapies, to a subset of chemoresistant tumors with low proliferation and luminal characteristics. This work was supported by Centro de Investigación Biomédica en Red de Cáncer (CIBERONC) from Instituto de Salud Carlos III (ISCIII) (CB16/12/00241, CB16/12/00471, CB16/12/00481) and by research grants from ISCIII (PI13/00730), Mutua Madrileña 2013 and Sociedad Española de Oncología Médica (SEOM) 2013. The authors acknowledge support through grant TIN2017-88728-C2-1-R from MICINN-SPAIN. Angela Santonja has a predoctoral grant PFIS-ISCIII (FI12/00489).