Advanced prostate cancer was defined as metastatic disease or Gleason score (GS) ≥ 8 or PSA >100 or prostate cancer death; early-onset refers to prostate cancer onset before age 55; low aggressive refers to T stage from the TNM staging ≤ T1, and GS ≤ 6, and PSA<10; intermediate aggressive refers to T stage: T2, and GS = 7, and PSA 10–20; and high aggressive refers to T stage: T3/T4 or N1 or M1 or GS ≥ 8 or PSA >20. Here, KLK3 is linked to prostate cancer.