KLK6 and oral cavity squamous cell carcinoma: KLK6 has been associated with other cancer types, for example melanoma, glioblastoma multiforme, non-small-cell lung cancer and oral squamous cell carcinoma, the central nervous system and inflammatory conditions, such as in skin and joint diseases, and signals through G protein-coupled proteinase-activated receptors (PARs) [15,29,30,31,32,33].