TMPRSS3 is a 437 amno acid membrane bound serine protease and a member of the S1 peptidase family. TMPRSS3 contains an amino-terminal signalanchor sequence and a glycosylated extracellular region containing the serine protease domain. Two novel missense mutations of TMPRSS3, W251C and P404L, alter the highly conserved amino acids of the serine protease domain. TMPRSS3 is expressed in many tissues, including fetal cochle,a a subset of pancreatic cancer and various other cancer tissues. TMPRSS3 is also overexpressed in cancer, suggesting that it may be important for processes in metastasis formation and tumor invasion.Synonyms: ECHOS1, TADG-12, TADG12, Transmembrane protease serine 3, Tumor-associated differentially-expressed gene 12 protein