KLK3 and prostate cancer: The mean value of the prostate specific antigen (PSA) taken from blood samples was 7.19 μg/L (SD ± 5.2), where the mean PSA level in patients with prostate cancer was 10.41 μg/L (SD ± 5.1) and those in healthy ones 4.1 μg/L (SD ± 4.2).