211 DOI: 10.1309/AJCPKSHXI3XEHW1J 211 © American Society for Clinical Pathology Anatomic Pathology / CDH17 in Gastrointestinal Carcinomas Tissue-Specific Cadherin CDH17 Is a Useful Marker of Gastrointestinal Adenocarcinomas With Higher Sensitivity

Cadherin 17 (CDH17) is a cell adhesion molecule expressed in intestinal epithelium and transcriptionally regulated by CDX2. We compared the usefulness of CDH17 as an immunohistochemical intestinal marker to that of CDX2 in gastrointestinal and extragastrointestinal carcinomas and nonneoplastic tissues. Nonneoplastic intestinal and pancreatic duct epithelia were CDH17-positive. Most esophageal (79%), gastric (86%), and colonic (99%) adenocarcinomas were CDH17-positive/CDX2-positive, whereas 1 % of colonic, 18 % of esophageal, and 10% of gastric adenocarcinomas were CDH17-negative/ CDX2-negative. Rare colonic, esophageal, and gastric adenocarcinomas were CDH17-positive/CDX2-negative (1%, 3%, and 4%, respectively), and none wer