Histological evaluation of mitotic and apoptotic index, Ki67, and p53 expression in repeated biopsies contributes to predicting the value of the actual treatment and may be useful to institute alterations in therapy.

A prospective study on 16 patients with advanced (stage III and IV) prostate cancer was carried out. TNM stage, general clinical status, serum PSA level, the histological type and Gleason’s grade of the tumor were registered. Total androgen blockade or single-drug therapy (flutamide) was performed. On average, 4.81 months after the start of therapy rebiopsy, serum PSA determination and general clinical examination were performed. Histologic examination before and after treatment of HE-stained slides, as well as apop-tag reaction to show apoptotic cells, p53, bcl₂, and Ki-67 immunostaining. Clinical improvement manifested by regression or lack of progression was observed in 10 patients. Increase of the apoptotic index and decrease of the mitotic index was detected in these cases. Serum PSA level decreased in all patients except in 3 fatal cases. The 6 clinically nonresponders who died after the second biopsy did not show an increased apoptotic or decreased mitotic index. Ki-67 positivity correlated well with the mitotic activity. Mutant p53 expression was higher in patients in whom antiandrogen therapy was ineffective. The bcl₂ expression was a characteristic of the tumors of patients who later died. These results show that the degree of induction of apoptosis in prostate carcinoma by hormonal therapy varies from case to case. A given prostate cancer patient’s response to therapy may be predicted by following apoptotic and mitotic activity, as well as Ki-67 and p53 expression in repeated biopsies.