KLK3 and cancer: Prostate cancer (PC) is the second most common cancer in men worldwide according to the World Health Organization GLOBOCAN database, and according to the Taiwan Cancer Registry Database (TCRD), a similar trend is noted in Taiwan.1,2 Furthermore, PC is the sixth major cause of male death in Taiwan.1 The current lifetime PC risk for men living in the United States is approximately 1 in 8,2 but PC incidence is highly dependent on screening using prostate-specific antigen (PSA) concentration and the number of PSA-driven biopsies.