PSGR, a novel prostate-specific gene with homology to a G protein-coupled receptor, is overexpressed in prostate cancer

PSGR, a new prostate tissue-specific gene with homology to the G protein-co upled odorant receptor gene family, has been identified. Here we report the characteristics of the predicted protein sequence of PSGR and its prostate tissue specificity and expression profile in human prostate cancer and mat ched normal tissues. Using multiple tissue Northern blots from over 50 diff erent tissues, PSGR expression was restricted to human prostate tissues. Pa ired normal and tumor specimens from 52 primary prostate cancers, obtained by laser capture microdissection or manual microdissection, were analyzed f or PSGR expression by semiquantitative and real-time PCR assays. The differ ential expression of PSGR between normal and tumor tissues was highly signi ficant (P < 0.001), and 32 of 52 (62%) matched prostate specimens exhibited tumor-associated overexpression of PSGR. Of note, there was very little or no expression of PSGR in many normal specimens in comparison with the gene rally high expression of PSGR seen in matched tumor specimens. In situ hybr idization assays showed restricted PSGR expression in the epithelial cells of the normal and tumor tissue sections. Restricted expression of PSGR in p rostatic epithelial cells, overexpression of the PSGR in a significant perc entage of prostate cancers, and the predicted protein sequence of PSGR with seven transmembrane domains provide a foundation for future studies evalua ting the potential of PSGR as a prostate cancer gene expression marker and the utility of PSGR protein as a novel target for developing immunotherapeu tic strategies for prostate cancer.