The introduction of prostate-specific antigen (PSA) screening almost 3 decades ago was followed by a substantial reduction in the incidence of metastatic disease, as well as a reduction in prostate cancer (PCa)–specific mortality.1 Despite these observations, the value of PSA screening has remained controversial because of the risk of overdiagnosis and overtreatment of low-risk PCa, which may outweigh the mortality reduction resulting from screening for higher-risk disease. Here, KLK3 is linked to prostate cancer.