Immunohistochemical (Ihc) Sub-Classification Of 105 Triple Negative Breast Cancers (Tnbc).

e12577Background: Molecular data have shown that TNBC was a heterogeneous group of tumors. The objective was to evaluate prognosis of IHC sub-classification adapted from molecular model. Methods: We used IHC sub-classification based on positivity for androgen receptor (AR) (Roche, SP 107), cytokeratine 5/6 (CK) (Dako, D5/16B4) and Epidermal growth factor receptor (EGFR) (Biosd, 31G7). Samples with more than 10% AR nuclear immunostaining were considered positive. Threshold for CK and EGFR was 1%. We distinguished 4 groups of tumors: AR phenotype (AR+, EGFR-, CK5/6-), basal-like phenotype (AR-, EGFR+/-, CK5/6 +/-), triple-negative phenotype (AR-, EGFR-, CK5/6-) and mixed group (AR+, EGFR+/-, CK5/6 +/-). Tissue micro-array blocks were constructed with samples from a retrospective cohort treated in adjuvant setting for non metastatic TNBC in a single institution from 2003 to 2013. Survival data were estimated by the Kaplan-Meier method and compared by the log-rank test in univariate analysis. Multivariate ana...