The European Randomized Study of Screening for Prostate Cancer (ERSPC) (Roobol and Schroder, 2003) and the Prostate Lung Colorectal and Ovarian cancer screening trial in the US (Prorok et al, 2000) offer screening by the PSA test in men aged 50–69 years (with some variation in age between participating countries). The gene discussed is KLK3; the disease is prostate carcinoma.