Prognostic significance of beta-microseminoprotein mRNA expression in prostate cancer

BACKGROUND. Human beta-microseminoprotein (beta-MSP or PSP94) is a small pr otein secreted by prostatic epithelial cells. We recently reported the pres ence of low levels of beta-MSP mRNA expression and protein in most prostate cancer tissues. METHODS. beta-MSP and mRNA expression was examined by in situ hybridization in biopsy specimens obtained from 92 patients with prostate cancer. AU tis sue specimens were obtained by needle biopsies prior to treatment. All pati ents subsequently received endocrine therapy. To estimate the influence of beta-MSP mRNA expression and three possible prognostic factors, i.e., patie nt age, clinical stage, and Gleason score, on time to progression under end ocrine therapy, univariate and multivariate analyses were performed using C ox's proportional hazards regression model. RESULTS. Multivariate survival analysis showed that clinical stage was the strongest prognostic factor (P =0.006) and that beta-MSP mRNA expression wa s the second strongest factor (P = 0.038) in 92 patients with stage B-D dis ease. Analysis of only 51 patients with stage D disease showed that beta-MS P mRNA expression was the only significant prognosis indicator for progress ion under endocrine therapy (P = 0.003). CONCLUSIONS. The presence of cells that express the beta-MSP transcript may be a novel indicator of potentially aggressive prostate cancer. (C) 1999 W iley-Liss, Inc.