KLK3 and prostate cancer: As a result of altered lifestyle, lengthened life expectancy, and increased prostate-specific antigen (PSA) screening, the national burden of prostate cancer (PCa) continues to increase in China.1 Although patient prognosis has improved in recent years because of early detection of PCa and timely intervention, a relatively large number of patients progress to biochemical recurrence within a few months following radical prostatectomy (RP).