KLK3 and prostate cancer: In the Cluster Randomized Trial of PSA Testing for Prostate Cancer (CAP) study in Great Britain, 419,582 men were randomized to a single PSA screening intervention versus standard practice of no screening, and the groups showed no significant difference in PCa mortality after a median follow-up of 10 years, although the detection of low-risk PCa cases was higher in the PSA screening group (20, 21).