The STHLM3 study prospectively demonstrated a 32% reduction in biopsies using the STHLM3 model compared to PSA ≥ 3 ng/mL for biopsy referral, without any loss in sensitivity, by also detecting GG ≥ 2 cancers for the PSA range 1–3 ng/mL and similar findings were achieved in the external validation of a multi-ethnic cohort [26,27]. This evidence concerns the gene KLK3 and cancer.