KLK3 and prostate cancer: Numerous studies of serum (PSA isoforms, prostate health index and other combinations), tissue (p63, AMACR, PSMA, Glutathione S-transferase P, etc.)and urine based (PCA 3, SPINK 1, Annexin A3, etc.)prostate cancer biomarker candidates have been presented during the last ten years (11-15).