Low apoptotic activity in primary prostate carcinomas without response to hormonal therapy

Proliferative and apoptotic activities, as well as p53 protein expression, of ten untreated primary prostate carcinomas that showed extremely poor res ponse to hormonal therapy (primary androgen independent prostate carcinomas ) were compared with the stage- and grade-matched primary tumor specimens w ith favorable response to hormonal therapy (androgen dependent prostate car cinomas). The mean proliferative activity measured by Ki-67 immunohistochem istry was slightly higher in the primary androgen independent prostate carc inomas (8.70+/-5.24) than in the androgen dependent prostate carcinomas (7. 09+/-2.68; p=0.27). The mean apoptotic activity by in situ end-labeling tec hnique in the primary androgen independent prostate carcinomas (0.96+/-1.03 ) was less than half of that in the androgen dependent prostate carcinomas (2.75+/-0.98; p=0.0001). Ten percent of the androgen dependent prostate tum ors showed p53 protein expression, whereas 30% of the primary androgen inde pendent prostate tumors were immunopositive for p53 (p=0.30), In summary, w e have shown that apoptotic activity in the primary androgen independent pr ostate carcinomas is significantly lower than in the matched androgen depen dent prostate carcinomas while the proliferative activity remains unaffecte d. These results suggest that primary androgen independent prostate carcino mas may have genetic properties, such as inactivation of the p53 gene, that enable them to escape apoptosis caused by androgen ablation.