The Prostate stem cell antigen (PSCA) is a glycosylphosphatidylinositol (GPI)-anchored protein, plays an important role in tumorigenesis. The prostate stem cell antigen (PSCA) gene, which encodes a prostate-specific antigen (PSA), was identified as a gene involved in cell adhesion and proliferation. PSCA may be involved in the regulation of cell proliferation. Has a cell-proliferation inhibition activity in vitro. May act as a modulator of nicotinic acetylcholine receptors (nAChRs) activity. In vitro inhibits nicotine-induced signaling probably implicating alpha-3:beta-2- or alpha-7-containing nAChRs.