Several factors make prostate cancer an ideal target disease for chemoprevention such as long latency, high incidence, and tumor markers availability (prostate-specific antigen, PSA), identifiable preneoplastic lesions; also, it is a very heterogeneous disease with a large subgroup of patients with nonaggressive disease (Van Poppel and Tombal, 2011 ▶). The gene discussed is KLK3; the disease is prostate carcinoma.