According to the National Comprehensive Cancer Network (NCCN) [10], observation, active surveillance, radiation, and radical prostatectomy are possible therapies for patients with very low (TMN Stage T1c, N0, M0; PSA < 10 ng/mL; Gleason grade ≤ 6) or low risk (TMN Stage T1a, T1b, or T2a, N0, M0; PSA < 10 ng/mL; Gleason grade ≤ 6) prostate cancer. Here, KLK3 is linked to prostate cancer.