5α‐REDUCTASE ACTIVITY IN HUMAN PROSTATE CANCER IS RELATED TO THE HISTOLOGICAL DIFFERENTIATION OF THE TUMOUR

Abstract

We have measured the activities of two androgen metabolizing enzymes in tissue obtained from thirty-nine patients with carcinoma of the prostate (CaP). The enzyme activities were correlated to the histological differentiation of the tumours based on the Gleason Score and also compared to the activities measured in fourteen age matched patients with nodular prostatic hyperplasia (BPH). Although the mean values for the 5α-reductase in CaP (9·29 ± 1·47 pmol/mg protein/30 min) were found to be significantly lower than the corresponding values in BPH (16·26 ± 3·04 pmol/mg protein/30 min) (P < 0·05), there were nonetheless significant differences within the cancer group and these were totally dependent on the degree of differentiation of the tumour. A progressively suppressed enzyme activity was measured as the carcinomatous tissue became more anaplastic. No correlation was, however, observed between tumour bulk which was also estimated histologically and 5α-reductase, indicating that the activity of this enzyme is purely a function of the histological grade of the cancer and as such 5α-reductase could be used as a biochemical marker for tumour differentiation. We also measured the 3α(β)-hydroxysteroid dehydrogenase activities in cancer of the prostate but our findings indicated no significant differences between the various stages of the cancer. Furthermore we were unable to correlate the activities of this enzyme with that of the 5α-reductase. Nonetheless two interesting patterns relating to the 3α(β)-hydroxysteroid dehydrogenase emerged. Whilst in BPH the activity of this enzyme was confined to a very narrow range (1·04 ± 5·27 pmol/mg protein/30 min), there was a wide spread in the activities of the cancerous specimens with the highest 3α(β)-hydroxysteroid dehydrogenase activity being usually manifested in specimens with a low 5α-reductase. Since the capacity of some cancerous specimens to metabolize