KLK3 and neoplasm: Interestingly, IR PCa patients presenting with a tumor involving one lobe (clinical stage T2b) or less, prostate-specific antigen (PSA) <10 ng/mL, and International Society of Urological Pathology (ISUP) grade group 3 represent a borderline subgroup in whom the risk of tumor upgrading (ISUP > 3) is a serious drawback due to the association with unfavorable tumor stage (extracapsular extension or seminal vesicle invasion) at final pathology, and eventually with tumor progression (9).