PSCA and neoplasm: Prostate stem cell antigen (PSCA) gene encodes a glycosylphosphatidylinositol-anchored cell membrane glycoprotein. In addition to being highly expressed in the prostate it is also expressed in the bladder, placenta, colon, kidney and stomach. This gene is up-regulated in a large proportion of prostatecancers and is also detected in cancers of the bladder and pancreas. The function of PSCA in tumor biology and the regulatory mechanism of PSCA expression still remains unknown.