EXPRESSION OF THE APOPTOSIS SUPPRESSING PROTEIN BCL-2 IN PROSTATIC ADENOCARCINOMA IS RELATED TO TUMOR MALIGNANCY

BACKGROUND. The expression of bcl-2 protein has been related to histop athological features and prognosis in several epithelial tumors. In pr ostatic adenocarcinoma the prognostic significance of bcl-2 expression is mainly unexplored. METHODS. The expression of bcl-2 protein was as sessed in 235 prostatic adenocarcinomas by using monoclonal bcl-2 prot ein antibody after microwave pretreatment of the cancer sections. The results of immunohistochemistry were related to histopathological feat ures and prognosis of the patients. RESULTS. 71% of the tumors were bc l-2 negative, in 18% of cases the expression was weak, and in 11% of c ases strong. The fraction of bcl-2 positive cells was variable (mean [ SE]: 15 [2]%). The expression of bcl-2 protein was positively correlat ed to high T-category, metastatic disease, and poor histological diffe rentiation of the tumor. Tumors that were aneuploid and rapidly prolif erating frequently expressed bcl-2 protein, while tumors we densely in filtrated by inflammatory cells rarely expressed bcl-2. The expression of bcl-2 protein was related to lowered survival probability in univa riate analysis, while in multivariate analysis the expression of bcl-2 had no independent prognostic value. CONCLUSIONS. The expression of b cl-2 protein in prostatic adenocarcinoma is related to tumor malignanc y, but the prognostic significance of the expression requires further analyses, particularly in localized tumors. (C) 1997 Wiley-Liss, Inc.