Different Prognostic Factors Correlate with Bcl-2 Expression among Triple Negative and Non-Triple Negative Breast Cancers

Abstract

Prognostication of breast cancer using clinico-pathologic variables, although useful, remains imperfect. Recent research has focused on finding new markers of prognosis using gene expression profiling. Panels of proteins assessed by immunohistochemistry might also be useful in this regard. This study focused on Bcl-2 protein expression in triple-negative (TNBC) and non- triple-negative breast cancer (non-TNBC) with correlation to clinico-pathologic variables. We analyzed Bcl-2 expression in 77 women with primary breast carcinoma divided into two groups; triple-negative and non- triple-negative according to expression of estrogen (ER), progesterone (PR) and human epidermal growth factor receptors (Her2/neu). Bcl-2 expression was assessed in relation to age, histo-pathological subtype, grade, nodal status and tumor size. Bcl-2 was expressed in 74% of triple-negative breast cancers and 70% of non- triple-negative cancers. In TNBC, expression was significantly correlated with invasive ductal subtype, while in non-TNBC it was significantly correlated with age and negative nodal status. In both groups higher Bcl-2 expression associated with favourable prognostic factors in breast cancer, but no significant statistical correlations were found. Frequency of Bcl-2 expression does not differ between TNBC and non-TNBC, but different prognostic factors correlate with Bcl-2 in the two cases.