This MAb recognizes an intermediate filament protein of 46kDa, identified as cytokeratin 20 (CK20). CK20 is abundantly expressed in goblet cells and enterocytes of the gastrointestinal tract. It is a useful marker of pancreatic and colorectal cancer. CK20 is expressed under normal, hyperplastic and neoplastic conditions. It has been detected in adenocarcinomas of the colon, stomach and biliary tract. Breast carcinomas are generally non-reactive.