KLK3 and colorectal cancer: Antibodies to target biomarkers are widely used, for detecting prostate specific antigen (PSA), specifically expressed in prostate cancer [65], carcinogenic-embryonic antigen (CEA) in colorectal cancer [66], CA15-3 antigen and her-2/neu are proteins associated with breast cancer [67,68], CA19-9 in gastrointestinal cancer [69], while CA125 is a biomarker for ovarian cancer diagnosis [70].