carbohydrate antigen 19-9

Mucus is the viscous secretion that covers epithelial surfaces (trachea, colon, and cervix) and consists of twenty highly glycosylated proteins called mucins. The mucin family all are high-molecular weight proteins with oligosaccharides attached to the serine or threonine residues of their core protein backbone by O-glycosidic linkages. Mucins play fundamental roles in mucosal cell protection, lubrication, and communication with their external environment as detailed by Corfield¹. They have been implicated in epithelial renewal and differentiation.