Detection of a Shared Colon Epithelial Epitope on Barrett Epithelium by a Novel Monoclonal Antibody

Abstract

To determine if there is a reactive epitope common to colonic epithelium and Barrett epithelium, a premalignant metaplastic columnar-lined esophagus, usually arising as a complication of chronic reflux esophagitis. A monoclonal antibody, 7E₁₂H₁₂ (IgM isotype), developed against a colonic epithelial protein was used in a sensitive immunoperoxidase assay using formalin-fixed, paraffin-embedded tissue. One hundred sixteen tissue specimens from the esophagus, stomach, duodenum, and jejunum were examined. Twenty-two biopsy specimens were taken from 22 patients with benign Barrett epithelium, and 12 specimens were obtained from 12 patients with adenocarcinoma of the esophagus arising in Barrett epithelium. The remaining 85 tissue specimens were obtained from various parts of the upper gastrointestinal tract of patients with or without disease states. 21 of 22 (95%) Barrett epithelium specimens and all 12 adenocarcinomas arising from Barrett epithelium reacted with the 7E₁₂H₁₂ monoclonal antibody. Other tissues from esophagus, gastroesophageal junction, stomach, duodenum, or jejunum did not react. Squamous cell carcinoma of the esophagus also did not react. Barrett epithelium shares phenotypic expression of colonic epithelium. The 7E₁₂H₁₂ monoclonal antibody may provide insight into the origin and cellular lineage of Barrett epithelium.