KLK3 and Familial prostate cancer: To prevent overtreatment of prostate cancer, active surveillance (AS) or focal therapy have been introduced for low risk (PSA < 10 ng/mL and Gleason score of 6 [Grade group (GG) 1] and cT1-2a) and highly selected intermediate risk (PSA 10–20 or Gleason score 3 + 4 [GG 2] or cT2b) localized prostate cancer patients [4, 5].