Three randomized controlled trials (RCTs) investigated the effect of PSA-basedscreening on PCa mortality: the Prostate, Lung, Colorectal and Ovarian CancerScreening [PLCO] trial of annual PSA screening (N  =  76,693); the EuropeanRandomized Study of Screening for Prostate Cancer [ERSPC] involving 2–4 yearlyscreening (N  =  162,243); and the Cluster Randomized Trial of PSA Testing forProstate Cancer [CAP] involving a single PSA screen (N  =  408,825). This evidence concerns the gene KLK3 and prostate carcinoma.