The best available evidence suggests that PSA screening may have a small, although uncertain, benefit on prostate cancer mortality.3 Evidence shows, however, that PSA screening also harms men because of false-positive test results and overdiagnosis and overtreatment of prostate cancer.3 Before the major prostate cancer screening trials reported their results,2,5,6 there was insufficient evidence to recommend for or against screening. The gene discussed is KLK3; the disease is Familial prostate cancer.