Histochemical detection of intranuclear DNA fragmentation and its relation to the expression of bcl-2 oncoprotein in human prostatic cancer.

OBJECTIVE To assess the incidence of intranuclear DNA fragmentation and the expression of the bcl-2 oncoprotein in prostatic carcinoma, both of which are related to programmed cell death. PATIENTS, MATERIALS AND METHODS Specimens of tumour obtained from 17 patients with newly diagnosed prostatic carcinoma and 16 with hormone-treated prostatic carcinoma undergoing total prostatectomy were evaluated. DNA fragmentation was detected using the terminal-labelling method (d-uridine triphosphate conjugated with digoxigenin) and the expression of bcl-2 was detected immunohistochemically. RESULTS There was a high incidence of intranuclear DNA fragmentation in 14 of 17 untreated tumours and 15 of 16 hormone-treated tumours. There were no differences between the positive cases in hormone-treated tumours and untreated tumours. There was significantly greater expression of bcl-2 in tumours treated with non-steroidal anti-androgen drugs (eight of nine were positive) than in those untreated (seven of 17) or treated with other drugs (one of seven) (P < 0.05). There was a consistent and marked dissociation between DNA fragmentation and bcl-2 positivity; most of the cells positive for bcl-2 showed no DNA fragmentation. CONCLUSION The results indicated that cells positive for bcl-2 might potentially be hormone resistant and that the administration of non-steroidal anti-androgen drugs might have a role in the induction of hormone-resistant cells.