CLINICAL-STUDY ON ESTRAMUSTINE BINDING (EMBP) IN HUMAN PROSTATE

To elucidate the characteristics of estramustine binding protein (EMBP ) in human prostate, tissue EMBP concentration was examined in 42 beni gn prostatic hypertrophy (BPH), 34 untreated prostatic carcinoma (PC), 8 hormone refractory PC (hr-PC), as well as 13 control prostate human tissue samples by RIA using rat-EMBP antibody, and the concentration thus obtained was compared with dihydrotestosterone (DHT), prostatic a cid phosphatase (PAP), prostate-specific antigen (PSA), and zinc, indi ces exhibiting androgen dependency in the prostate. EMBP concentration correlated significantly with DHT and PSA levels in the control prost ate and BPH, but not in untreated PC. In BPH, EMBP concentration incre ased significantly after administration of fluoxymesterone (4 mg/day f or 2 weeks), whereas it decreased significantly after estramustine pho sphate (280 mg/day for 2 weeks). The EMBP/DHT ratio in moderately and poorly differentiated, and the hr-PC was significantly higher than in controls, BPH, and well-differentiated PC. In addition, untreated PC w ith an EMBP/DHT ratio of more than 40 showed significantly lower progr ession-free probability as compared with PC with an EMBP/DHT of less t han 40. These results suggest that (1) EMBP in BPH and well-differenti ated PC preserves androgen dependency, but not in moderately and poorl y differentiated, nor in hr-PCs, indicating that EMBP is a protein dif ferent from PAP and PSA, and (2) that the tissue EMBP/DHT ratio might be useful as a marker for predicting disease progression. (C) 1996 Wil ey-Liss, Inc.