Expression of cyclooxygenase-1 and cyclooxygenase-2 in the human prostate

Objectives. To determine the cell-specific expression of the two major isof orms of cyclooxygenase (COX-1 and COX-2) in human noncancerous and cancerou s prostatic tissues. Methods. Thirty-one specimens of prostate carcinoma (CaP) and 10 specimens of benign prostatic hyperplasia (BPH) were stained with mouse antihuman COX -1 and COX-2 monoclonal antibodies. The stained specimens were analyzed bot h descriptively and in a semiquantitative manner by assigning an immunoreac tive intensity score (0 to 4). The averaged results were compared for diffe rent histologic tissue types, including luminal and basal epithelium of BPH , the peripheral zone, high-grade prostatic intraepithelial neoplasia (PIN) , and CaP of varying Gleason grades. Results. COX-1 expression in noncancerous prostatic tissue was seen predomi nantly in the basal epithelial cells of BPH (90% positive staining). COX-1 expression was minimal in noncancerous luminal epithelial cells (0% to 10%) but was upregulated in CaP (63% of CaP specimens). Strong COX-2 expression was demonstrated in the smooth muscle cells of the prostate. COX-2 was als o expressed in the basal epithelial cells (60% BPH, 94% peripheral zone, 75 % PIN]. Luminal epithelial cells derived from BPH, the peripheral zone, and PIN expressed COX-2 in 0%, 26%, and 86% of samples, respectively. COX-2 ex pression in CaP was intense and uniform, with 87% of samples demonstrating immunoreactivity. Conclusions. The results of the present study indicate that expression of b oth COX-1 and COX-2 in human CaP is increased. COX-2 expression is also inc reased in the basal and luminal epithelial cells of PIN. These data indicat e that COX-1 and COX-2 (and/or their prostaglandin products) may play a rol e in the malignant transformation of the prostate. UROLOGY 56: 671-676, 200 0. (C) 2000, Elsevier Science Inc.