KLK3 and cancer: Of the 433 patients enrolled in AS between 2009 and 2016, 358 complied with AS inclusion criteria (Cancer of the Prostate Risk Assessment (CAPRA) score ≤ 5, Gleason grade group (GGG) ≤ 2, clinical stage ≤ cT2 and prostate-specific antigen (PSA) ≤ 20 ng/ml) and discontinuation criteria (histological-, PSA-, clinical- or radiological disease reclassification).