Prostate-specific antigen (PSA, Kallikrein-3, KLK3) is a serine protease that is usually secreted from the prostate gland and presented in seminal plasma. PSA function in the liquefaction of seminal coagulum, through hydrolysis of the high molecular mass seminal vesicle protein. Its substrates includes semenogelin I & II, fibronectin, insulin-like growth factor binding protein 3 (IGBP3), and laminin . Highly expressed by normal and malignant prostate cancer cells, PSA has been implicated in the growth, invasion, and metastasis of prostate cancer cells . Therefore, PSA is widely used as a diagnostic marker for prostate cancer. Recently, PSA has been suggested as an endothelial cell-specific inhibitor of angiogenesis .