Aberrant expression of MUC1 mucin in pediatric inflammatory bowel disease.

Mucin 1 (MUC1) glycoprotein is normally expressed at low levels on the luminal side of healthy colonic epithelial cells. In colon cancer and other epithelial tumors, MUC1 is overexpressed and hypoglycosylated. Antibodies specific for this "tumor form" of MUC1 are found in cancer patients.