Although the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial initially found no significant reduction in 10-year prostate cancer–specific mortality with screening,16,17 partly because of high contamination rates (nearly 50% of men in the no-screening arm were still receiving PSA tests), the European Randomized Study of Screening for Prostate Cancer trial demonstrated a 20% reduction in prostate cancer–specific mortality with routine PSA screening.11-13. The gene discussed is KLK3; the disease is prostate cancer.