The MUC6 secretory mucin gene ts expressed in a wide variety of epithelialtissues

Secretory mucins play an important role in the cytoprotection of epithelial surfaces and are used as tumour markers in a variety of cancers, The MUC6 secretory mucin was originally isolated from a gastric cDNA library, The ai m was to determine the specific type and location of MUC6 mucin gene expres sion in a wide range of human adult and fetal epithelial tissues, In situ h ybridization, RNA analysis, and immunohistochemistry were used to quantify and localize mucin gene expression. The data obtained show that MUC6 is hig hly expressed in gastric mucosa, duodenal Brunner's glands, gall bladder, s eminal vesicle, pancreatic centroacinar cells: and ducts, and periductal gl ands of the common bile duct; focal expression is seen in basal endometrial and endocervical glands. MUC6 epitopes were also highly expressed in 7/10 pancreatic cancers and 7/10 cholangiocarcinomas and focally expressed in 4/ 10 endocervical adenocarcinomas, Expression of MUC6 occurs early in fetal d evelopment and was observed in Brunner's glands and pancreatic ducts at 18- 19 weeks and in gastric glands at 20 weeks' gestation. The tissue distribut ion of the MUC6 secretory mucin indicates that it may function to protect e pithelial tissues from a wide range of substances, Expression of MUC6 is fr equently prescribed in pancreatic and bile duct adenocarcinomas, but it is only sparsely expressed in endocervical carcinomas. (C) 1998 John Wiley & S ons, Ltd.