KLK4 and neoplasm: Together with factor XII, kallikreins, kinins, and kininases, it is involved in the regulation of multiple organs and diverse pathophysiological processes such as cardiovascular, renal, nervous system, tumor, thrombosis, atherosclerosis and cell proliferation, inflammation, and apoptosis (Albert-Weissenberger, Siren & Kleinschnitz, 2013; Puchades et al., 2003; Regoli & Gobeil, 2015; Rhaleb, Yang & Carretero, 2011).