DETECTION OF APOPTOSIS BY THE TUNEL TECHNIQUE IN CLINICALLY LOCALIZEDPROSTATIC-CANCER BEFORE AND AFTER COMBINED ENDOCRINE THERAPY

Aims - Apoptosis in prostate cancer was evaluated after three months o f combined endocrine therapy to investigate the association with tumou r grade, tumour stage, and the immunohistochemical detection of p53 an d bcl-2 in tumour cells before and after therapy. Methods - Twenty six formalin fixed, paraffin wax embedded core biopsies and corresponding prostatectomy specimens, excised after three months of combined endoc rine therapy, were analysed for the presence of apoptotic cells by the terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end l abelling (TUNEL) method, and for p53 and bcl-2 overexpression by immun ohistochemistry. Results - All 26 adenocarcinomas were clinically loca lised at diagnosis. In biopsies performed before combined endocrine th erapy, the apoptotic indices varied between 0.09% and 1.73%, while the tumour grade fell between Gleason score 1 and 8. The mean (SD) apopto tic count pretherapy was 0.71% (0.50). There was a significant associa tion between elevated apoptotic counts and higher Gleason scores in th e biopsies (p = 0.005). After three months of therapy, the percentage of apoptotic tumour cells increased independently of tumour stage, whi le a significant association with Gleason grade was found (p = 0.0018) and all the tumours had Gleason scores of < 7. In eight cases the apo ptotic index was more than twice its pretherapy value. The remaining t umours showed less of an increase in the apoptotic index (five cases) or a reduction in the percentage of apoptotic cells. The overall moder ate increase in apoptotic index after combined endocrine therapy was n ot statistically significant (p = 0.8). Immunoreactivity to p53 was ab sent in all cases, before and after therapy, while a slight increase i n the number of cells overexpressing bcl-2 was observed in five of the 13 tumours (38.1%) with reduced apoptotic indices after therapy. Conc lusions - After three months of combined endocrine treatment a minorit y of clinically localised prostate neoplasms showed regressive epithel ial alterations, associated with an increase in apoptotic tumour cells ; an increase in cells overexpressing bcl-2 was observed in five of th e 13 tumours with reduced apoptotic indices.