EVALUATION OF IMMUNOHISTOCHEMICAL ANTI-APOPTOTIC BCL-2 AND PRO-APOPTOTIC BAX GENE PRODUCTS IN BREAST CARCINOMA
Eman MS Muhammad1, Amal N Ahmad2,Marcelle NGuirguis3,Asem Elsani M Ali4
Department of Pathology1-2, and Surgery4 Sohag Faculty of MedicineDepartment of Clinical Pathology3, Assiut Faculty of Medicine.
One of the greatest challenges in breast cancer management is to accurately predict the outcome for each patient. To do this at present, we rely heavily on traditional pathological variables, such as tumor size, tumor grade and lymph node status. However, despite the broad applicability of clinic-pathological indices, they are still unable, to separate the 30% node-negative patients who will relapse from the 70% who will not. We aimed to: 1. Study the immunohistochemical profile of bcl-2 and bax in breast carcinoma. 2. Assess their prognostic values in relations to clinico-pathological prognostic factors. Subjects and methods: This study included 45 specimens of breast carcinoma. Patient’s age, tumor size and local aggressive changes, history of recurrence and/or presence of distant metastasis were obtained. Sections stained with H&E were evaluated for the presence of benign breast disease, tumor type and tumor grade, presence of in situ component, lymphocytic infiltration, lymphovascular invasion and axillary lymph node status. Immunostaining was done to detect the expression of bcl-2 and bax. Results: Both bcl-2 and bax were regularly expressed in areas of benign breast disease. Bcl-2 was positive in all ductal carcinoma in situ (DCIS); 100% of grade I, 89% of grade II and 87% of grade III invasive breast carcinoma (IBC). Bcl-2 was inversely correlated to tumor grade of IBC (p<0.03) and to lymphocytic infiltration (p<0.02). Bax was positive in (80%) low grade, (100%) intermediate and high grade DCIS. Bax was positive in (83%) grade I IBC and in all (100%) grade II and grade III IBC. Bax expression was positively correlated to: tumor grade (p<0.05) and lymphocytic infiltration (p<0.00). No significant difference in either bcl-2 or bax expression in lymph nodal positive or negative cases. In DCIS; negative correlation was present between bcl-2 and bax (p<0.01). In IBC; insignificant correlation was present between bcl-2 and bax. Conclusions: Bcl-2 is an indicator for good prognosis in breast cancer being negatively correlated to tumor grade and prominent lymphocytic infiltration. Bax is an indicator for poor prognosis in breast cancer being positively correlated to tumor grade and presence of prominent lymphocytic infiltration. Abbreviations: NCI; National Cancer Institute, DCIS; ductal carcinoma in situ, IBC; invasive breast carcinoma, IDC NOS; infiltrating duct carcinoma, not otherwise specified, PBS; phosphate buffered solution, SI; Staining intensity, PP; percentage of positive tumor cells, IHCS; immunohistochemical scores.