Estimation of BCL-2 protein in carcinoma of the breast and its clinical correlation in locally advanced breast cancer

Abstract

The change in expression of apoptotic markers (Bcl-2 and Bax proteins) brought about by various chemotherapeutic regimens is being used for its predictive value for assessing response to neoadjuvant chemotherapy (NACT) in locally advanced breast carcinoma (LABC). (1) Estimation of Bcl 2 expression in LABC, (2) Any change in Bcl 2 expression following chemotherapy in LABC, (3) Any relation of Bcl 2 estimation to changes in size of tumor, nodal status, age, and menopausal status. This was a prospective study of 120 cases of LABC. All cases were subjected to biopsy and the tissue was evaluated immunohistochemically for apoptotic marker Bcl-2 family protein. Three cycles of NACT were given at three-weekly intervals. Modified radical mastectomy was performed and the specimens were re-evaluated for any change in the Bcl-2 family protein. The clinical response and immunohistochemical response were correlated and compared. Coefficient of correlation was calculated by Pearson correlation coefficient (P-value). Clinical response, as measured by reduction in the tumor size, was observed in 81 (67.5%) patients while immunohistochemical response was observed in 67 (55.8%) patients. Correlation between immunohistochemical and clinical response was found to be statistically significant (P = 0.02). Nodal response was seen in 72 (60%) patients. There were no patients in the N o group; 22 (53.7%) of the N 1 patients were down-staged to N o , while 19 (46.3%) remained N 1 . In patients with N 2 disease, 11 (13.9%) were down-staged to N o status, 39 (49.4%) were down-staged to N 1 status, and 29 (36.7%) did not show any response. Immunohistochemical response was observed in 67 (55.8%) patients. Correlation between immunohistochemical and nodal responses was also found to be statistically significant (P = 0.03). This significant positive correlation between clinical and immunohistochemical responses highlights the importance of apoptotic marker Bcl-2 family protein in predicting the response of LABC to NACT.