Immunohistochemical Characterisation of Basal Like Phenotype of Triple Negative Breast Cancer from Western India

Background and Aim: Triple-negative breast cancer (TNBC), which accounts for approximately 1520% of all breast cancers, defined as lack of expression of estrogen receptor, progesterone receptor and Her-2 neu receptors. TNBC has two subtypes basal like and non-basal like, the former characterised by aggressive biology with limited therapeutic options. The present study aimed to identify TNBC with basal like phenotype and its correlation with conventional parameters. Method: This study enrolled 100 untreated TNBC and immunohistochemical localisation of CK5/6, CK14, CK17, EGFR, Vimentin and C-kit was performed on tumor tissues for identification of basal like phenotype. The data was analysed statistically using SPSS software version 20. Results: CK5/6, CK14, CK17, EGFR, Vimentin and C-kit expression was seen in 36%, 4%, 45%, 45%, 50% and 38% TNBC, respectively. Of 100 TNBC patients, 77% were positive for basal marker expression identified as basal like and 23% were negative for basal marker expression identified as Non-Basal. Further, multivariate analysis by General Linear Model indicated that four markers combination (vimentin, EGFR, CK17, CK5/6) has maximum 1.00 observed power of the test for identification of Basal-like TNBCs. In univariate and multivariate survival analyses, none of the marker discriminated patients with worse or better relapse free survival. Conclusion: A panel of markers includes Vimentin, EGFR, CK17 and CK5/6 can be used for classification of basal like TNBCs.