Cytokeratin 20 is a member of the keratin family of intermediate filament proteins responsible for the structural integrity of epithelial cells. Cytokeratin 20 is a type I cytokeratin, acidic proteins which are arranged in pairs of heterotypic keratin chains. This cytokeratin is a major cellular protein of mature enterocytes and goblet cells and is specifically expressed in the gastric and intestinal mucosa. [taken from NCBI Entrez Gene (Gene ID: 54474)].