KLK3 and prostate cancer: When serum PSA levels were subdivided into five categories according to the serum PSA levels (less than 4.0, 4.0 to 10.0, 10.0 to 20.0, 20.0 to 100.0, and ≥ 100.0 ng/ml), the detection rates of prostate cancer were 30.0, 22.6, 36.0, 59.1, and 93.5%, respectively (Table 2).