These enzymes(expressed in the nucleus and cytoplasm of, for example, prostate epithelial cells) (10) are encoded by the 5α-reductasetype 2 (SRD5A2) gene, and polymorphisms of this gene (leading to increased5α-reductase activity and DHT concentrations in prostate) have beenhypothesized to increase risk of prostate cancer (11). The gene discussed is SRD5A2; the disease is prostate cancer.