KLK3 and cancer: Biomarkers associated with the diagnosis and prognosis of rapid and early clinical cancer stages show over-expression of numerous genes and proteins, including prostate-specific antigen (PSA), Cancer antigen 125 (CA-125), Carcinoembryonic antigen (CEA) test, Cancer antigen 19-9 (CA19-9), among others, despite these antigen-associated biomarkers are less specific and more sensitive to the demand for multiple biomarkers to diagnose specific cancer types and stages [64, 65].