KLK3 and Familial prostate cancer: Several biomarkers are currently used in clinical practice to aid cancer diagnosis and management, such as Carcinoembryonic Antigen (CEA) in colorectal cancer, Bladder Tumour Antigen (BTA) in bladder cancer, Prostate Specific Antigen (PSA) in prostate cancer [14], Cancer Antigen 125 (CA125) in ovarian cancer, and the BRCA1/2 mutation in breast and ovarian cancer [15] (Table 1).