The MUC6 gastric mucin is a secreted glycoprotein that plays an essential role in epithelial cyto-protection from acid, proteases, pathogenic microorganisms, and mechanical trauma in the gastrointestinal tract. Mucin 6 expression is highest in the stomach and gall bladder, with lower expression in the terminal ileum and right colon. In gastric cancer, Mucin 6 has an altered expression. In normal stomach, Mucin 6 is associated with Lewis type 2; Mucin 6 is also expressed in gastric metaplasia, duodenum and pancreas. Mucin 6 is a secretory mucin, located in the deeper mucosal folds of human gall bladder, and its expression is altered with increasing degrees of inflammation.