KLK3 and neoplasm: The diagnostic panels include PSA isoforms, PSA density and velocity, age-adjusted PSA, free PSA to total PSA ratio (fPSA/tPSA), PSA density (PSAd), PSA doubling time (PSADT), Prostate health index (Phi), 4K score (include kallikrein-related peptidase 2/hK2, intact PSA, fPSA, and tPSA), advanced MRI (mpMRI and bpMRI), PCA3 mRNA, PSA glycoforms, TMPRSS2:ERG fusion gene, microRNAs, circulating tumor cells (CTCs), and androgen receptor variants [5, 9–12].