Human tissue kallikrein (KLK1) is a serine protease, component of the KKS that has been demonstrated to exert pleiotropic beneficial effects in protection from tissue injury through its antiinflammatory, antiapoptotic, antifibrotic and antioxidative actions.Polymorphism of the human tissue kallikrein 1 (KLK1) A1789G gene is associated with susceptibility to hypertension.