KLK3 and diabetes mellitus: DM: diabetes mellitus, PCa: prostate cancer, BPH: benign prostatic hyperplasia, PSA: prostate-specific antigen, ROS: reactive oxygen species, TZDs: thiazolidinediones, GLP-1RAs: glucagon-like peptide-1 receptor agonists, SGLT-2is: sodium-glucose transport protein 2 inhibitors