Gonadotropin-releasing hormone receptors in prostate tissue

OBJECTIVE: To perform an immunohistochemical analysis of gonadotropin-releasing hormone receptors (GnRH-Rs) in archival prostate tissue. STUDY DESIGN: Thirteen benign prostatic hyperplasia (BPH) specimens from open surgery, 48 radical prostatectomy specimens (30 surgery only and 18 neoadjuvant hormone treatment and surgery) and 14 prostate needle biopsies were examined. The avidin-biotin-peroxidase technique and monoclonal antibody A9E4 against the extracellular domain of GnRH-Rs were employed. Cases with > 5% immunoreactive cells (IR) were considered positive. RESULTS: The epithelium from all 13 cases of BPH was immunoreactive. Most tumor cells from biopsies were IR positive. Twenty-seven of 30 surgery-only specimens were IR positive vs. 8/18 in the surgery and neoadjuvant hormone treatment group. CONCLUSION: GnRH-Rs have been histochemically demonstrated in normal lutenizing hormone/ follicle-stimulating hormone pituitary cells. In cell lines LN-CaP and DU-145, Gn-RH-R was identical to that of the pituitary. GnRH-Rs in the prostate can be quite easily assessed immunohistochemically in archival tissue samples, and hormone treatment significantly decreases the immunoreactivity of GnRH-Rs in prostate cancer tissue. This strongly suggests that GnRH agonists bind to BPH and prostate cancer cells.