Prostate stem cell antigen is 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 prostate cancers and is also detected in cancers of the bladder and pancreas. This gene has a nonsynonymous nucleotide polymorphism at its start codon.Highly expressed in prostate. Also found in bladder, placenta, stomach, colon and kidney. Overexpressed in prostate cancers and expression is correlated with tumor stage, grade and androgen-independence. Highly expressed in prostate cancer bone metastases. Expressed in gastric epithelial cells, mainly in the isthmus (at protein level). Not detected in normal intestinal epithelium (at protein level).