KLK3 and prostate cancer: The biological significance of altered glycosylation for cancer detection is further highlighted by the fact that several cancer biomarkers currently used in the clinic are glycoproteins e.g., Her2/neu in breast cancer, CA-125 in ovarian cancer, prostate specific antigen (PSA) in prostate cancer, carcinoembryonic antigen (CEA) and cancer antigen 19-9 (CA-19-9) in CRC [10,82].