Although much lower than that in Western countries, the incidence of prostate cancer (PCa) in the People's Republic of China has been rapidly increasing over the past few decades.1 According to the Chinese Cancer Registry Annual Report (2012), PCa ranks as the 6th most prevalent cancer and the 9th leading cause of cancer-related mortality in men, especially in urban area.2 Altered lifestyle, lengthened life expectancy, and increased prostate-specific antigen (PSA) screening likely contribute in part to the increase in PCa diagnosis. Here, KLK3 is linked to cancer.