Immunohistochemical Expression of B-Cell Lymphoma-2 Gene with Clinicopathological Correlation: A Comparative Analysis of Triple Negative and Non-Triple Negative Breast Cancers

Abstract

Background: B-Cell Lymphoma-2 gene is an anti-apoptotic protein associated with favorable prognosis in patients with breast cancer. The present study focused on immunohistochemical expression of the aforementioned gene with clinicopathological correlation in non-triple negative breast cancers (NTNBCs) and triple negative breast cancers (TNBCs).

Methods: We investigated 258 cases of primary breast cancers; they were divided into 2 groups (NTNBCs and TNBCs) based on their expression of estrogen receptor (ER), progesterone receptors (PR), and Her-2/neu receptors. BCL-2 expression was correlated with age, tumor size, tumor grade, histological subtype, lymph node status, and lymphovascular invasion (LVI).

Results: Among NTNBCs, 68.2% of cases expressed BCL-2 as compared to 53.3% in TNBCs (P-value = 0.035). In both groups, BCL-2 expression was significantly higher in younger patients, without lymphovascular invasion and lower grade (borderline significant in TNBCs). The variable which was associated with higher BCL-2 expression only in NTNBCs was smaller tumor size. In contrast, in TNBCs invasive ductal carcinoma was significantly associated with BCL-2 expression.

Conclusions: BCL-2 showed association with various clinicohistopathological characteristics in TNBC and NTNBC breast cancer patients. Yet, some of these variables were potentially related to better prognosis (the lack of LVI, smaller tumor size, and lower grade). On the other hand, younger age, which is a feature generally associated with poorer prognosis, was significantly related to BCL-2 expression.