Among the glutathione S-transferases (GSTs), a family of detoxification enzymes catalyzing the conjugation of glutathione with a large number of carcinogens, placental GST (GST P) is specifically expressed during rat hepatocarcinogenesis and has been used as a reliable tumor marker for experimental hepatocarcinogenesis in rats (21). The gene discussed is HPGDS; the disease is neoplasm.