TMPRSS4 (gene ID 56649; chromosomal location 11q23.3), initially referred to as TMPRSS3 but also known as CAP2 or MT-SP2, was originally identified as a gene strongly expressed by most pancreatic carcinoma tissues but not in the normal pancreas or in cases of chronic pancreatitis44. Here, TMPRSS4 is linked to exocrine pancreatic carcinoma.