Increased expression of prostate-specific G-protein-coupled receptor in human prostate intraepithelial neoplasia and prostate cancers

The G-protein-coupled receptors and signal transduction pathways represent important specific targets for a variety of human diseases, ranging from the control of blood pressure, allergic response, hormonal disorders and neurologic diseases to tumorigenesis. Most recently, we and others have identified a novel human prostate-specific G-protein coupled receptor (PSGR). To investigate the potential roles of PSGR in human normal prostate and prostate cancers, we examined the expression level of PSGR in 146 human prostate samples with real-time quantitative reverse transcription-PCR and in situ hybridization method. We significantly extended previous studies and demonstrated that PSGR is specifically expressed in human prostate tissues, not in any other normal and tumor samples tested. Compared to normal and benign prostatic hyperplasia tissues, the expression of PSGR increased significantly in human prostate intraepithelial neoplasia (PIN) and prostate tumors (approximately 10-fold), especially in early prostate tumors, suggesting PSGR may play an important role in early prostate cancer development and progression. The sensitivity and specificity estimates for PSGR expression were calculated as the area under the receiver-operating characteristics curve (0.902), indicating high-level sensitivity and specificity for discriminating benign prostate tissues from malignant prostate tissues. The association of PSGR expression with clinical parameters (clinical stages, Gleason scores, recurrent status and metastasis) was also investigated in this study. Our data suggest that overexpression of PSGR in human PIN and prostate cancers have the potential for early prostate cancer detection and diagnosis.