Prostate-cancer-related death has diminished due to the extensive applications of prostate-specific antigen (PSA) testing; however, the overall downward trend of mortality stabilized after 2013, which is probably because of the recommendation of the United States Preventive Services Task Force (USPSTF) against PSA screening in 2012 and the rising diagnostic rates of late-stage prostate cancer [2]. Here, KLK3 is linked to prostate cancer.