MUC5AC and Barrett esophagus: For example, aberrant MUC5AC expression has been found in intraductal papillary mucinous neoplasia and pancreatic cancers, suggesting that MUC5AC can aid in assuring the diagnosis of pancreatic carcinomas,19 classifications of gastric polyps and Barrett metaplasia,20 or as a diagnostic tool in the dermapathology.21 It is also suggested that MUC5AC expression is helpful to distinguish between sessile serrated adenomas/polyps and hyperplastic polyps.22 Studies analyzing MUC5AC expression in cancers by immunohistochemistry (IHC) have described highly variable data.