Currently, in Japan, PSA screening often triggers a diagnosis of prostate cancer, yet the mean serum PSA level of 9.18 ng/mL in this study was nearly 1.5 times that reported in many other Western studies; for example, the mean serum PSA value was 6.9 ng/mL in the series reported by Patel et al. [18]. The gene discussed is KLK3; the disease is prostate cancer.