Triple Negative Breast Cancer: Immunohistochemistry-Based Sub-Classification and Correlation with Clinico-Demographic...

In India, breast cancer number is increasing at an alarming pace in younger women. Majority of the patients are presenting in an advanced stage and are frequently showing triple negative phenotype. Additionally, in India, triple negative breast cancer (TNBC) prevalence is much higher in comparison to the western world. We undertook this study with an aim to characterize TNBC based on a panel of immunohistochemical markers to explore their pathogenesis, behavior, treatment response, and outcomes in respect to disease progression, disease-free survival, and death. The study was approved by Institutional Ethics Committee which included 63 TNBC cases for evaluating expression of GATA3 and p53. Basal cell markers were done only in GATA3 negative cases. The IHC markers were correlated with different clinical profile, demographic factors, and outcome. A total of 63 patients were included in the study out of which 37 patients had disease-free survival; 8 patients showed disease progression; and 18 patients died. Among the patients, 29 were GATA positive. Out of those 29 patients, 15 were also p53 positive. Among 34 GATA3 negative cases, 32 showed expression of at least one basal cytokeratin marker, and 13 were also showed p53 expression. Among clinical factors tumor size (OR = 0.37; 0.15-0.81; P = 0.01), and tumors of grade III (OR = 0.02; 0.001-0.22; P = 0.004) showed significant association with reduced survival. BLBC forms a major part of TNBCs in the Indian patients. High tumor grade and large tumor size were significantly associated with reduced disease-free survival. Among immunohistochemistry markers, GATA3 positivity, GATA3 negative with p53 positivity, and CK positive with p53 positive cases showed decreased survival, however, the results were not statistically significant.

The online version contains supplementary material available at 10.1007/s13193-024-02141-3.