Kallikrein 5

The human tissue kallikrein (KLK) gene family contains 15 members that play important roles in cancer. Notably, kallikrein-1, also known as tissue kallikrein, cleaves kininogen to release the vasoactive kinin peptide, bradykinin or lysyl-bradykinin. Kallikrein-3, called prostate specific antigen (PSA), is an established tumor marker that aids in the diagnosis, staging, and follow up of prostate cancer. Kallikrein-4 is specifically expressed in the prostate and over-expressed in prostate cancer. Kallikrein-5 is widely expressed but found at high levels in skin, breast, brain and testis; over-expression is an indicator of poor prognosis in ovarian cancer. Kallikrein-8 is expressed in the brain and is a novel marker of ovarian and cervical cancer.