KLK6 (kallikrein-related peptidase 6), also known as Klk7, belongs to the peptidase S1 family, Kallikrein subfamily. Kallikreins are a subgroup of serine proteases having diverse physiological functions. Growing evidence suggests that many kallikreins are implicated in carcinogenesis and some have potential as novel cancer and other disease biomarkers. KLK6 is a serine protease which exhibits a preference for Arg over Lys in the substrate P1 position and for Ser or Pro in the P2 position. Klk7 shows activity against amyloid precursor protein, myelin basic protein, gelatin, casein and extracellular matrix proteins such as fibronectin, laminin, vitronectin and collagen. KLK6 degrades alpha-synuclein and prevents its polymerization, indicating that KLK6 may be involved in the pathogenesis of Parkinson disease and other synucleinopathies. Klk7 may be involved in regulation of axon outgrowth following spinal cord injury. Tumor cells treated with a neutralizing KLK6 antibody migrate less than control cells, suggesting a role in invasion and metastasis.