Cytokeratin and DAS-1 immunostaining reveal similarities among cardiac mucosa, CIM, and Barrett's esophagus

The normal histology at the gastroesophageal junction, and in particular the nature of cardiac mucosa, remains in dispute. Likewise, the relationship of intestinal metaplasia at the gastroesophageal junction (CIM) to Barrett's and intestinal metaplasia of the stomach (GIM) is unclear. The aim of this study was to assess the immunostaining characteristics of cardiac mucosa and CIM and compare their staining pattern with that of other foregut mucosal types. We hypothesized that the immunostaining patterns of these foregut tissues would provide insight into the nature and etiology of cardiac mucosa and CIM. Paraffin-embedded biopsy specimens from 50 patients with normal antral or fundic mucosa, cardiac mucosa, squamous mucosa, CIM, GIM, or Barrett's were obtained and immunostained with a panel of monoclonal antibodies including those for cytokeratins 7 and 20 (CK7/CK20) and DAS-1. Biopsies from normal gastric antral and fundic mucosa and squamous esophageal mucosa all showed a non-Barrett's type CK7/CK20 immunostaining pattern, whereas in 85% of patients, cardiac mucosa had a Barrett's type CK7/CK20 pattern (p