Kallikrein 9 (KLK9)

KLK9 belongs to the kallikrein subgroup of serine proteases, which have diverse physiologic functions in many tissues.KLK9 is primarily expressed in thymus, testis, spinal cord, cerebellum, trachea, mammary gland, prostate, brain, salivary gland, ovary, and skin.KLK9 is under steroid hormone regulation in ovarian and breast cancer cell lines and is a potential prognostic marker for early-stage ovarian and breast cancer patients.Based on homology between the human and mouse kallikrein loci, Yousef and Diamandis defined a 300-kb human kallikrein gene region on chromosome 19q13.3-q13.4. Within this region, they identified a new kallikrein gene, KLK9, which they designated KLKL3. The deduced 250-amino acid KLK9 protein has a predicted molecular mass of 27.5 kD and shares 40% amino acid sequence identity with KLK11.