Apoptosis in prostatic adenocarcinomas; A study of relationship to Ki-67 and bcl-2 protein expression

Background: Tissue samples from patients with prostatic adenocarcinoma (PCA) were examined for relationship between apoptosis and expression of Ki-67 and bcl-2 protein. Materials and Methods: Prostatic tissue was obtained from 29 prostatic cancer patients with no prior therapy. The number of apoptotic cells (apoptotic index; AI) and the percentage of Ki-67 stained cells (Ki-67 labeling index; LI) were compared with the expression of bcl-2 which was evaluated by the proportion and intensity of tumor cell immunostaining. Results: Both AI and LI of moderately and poorly differentiated PCAs were significantly higher than those of well differentiated PCAs. There was a significant correlation between AI and LI. Bcl-2 protein was expressed less in moderately and poorly differentiated PCAs than in well differentiated PCAs. Moreover, there was no correlation between the bcl-2 protein expression and the AI. Conclusions: The results suggest that, in PCAs, the degree of apoptosis is correlated with the cellular proliferation, and that expression of bcl-2 protein is not a critical factor that determines the degree of apoptosis.