Barrett's esophagus, morphologically analogous to gastric intestinal metaplasia, often precedes the development of esophageal adenocarcinoma. In the stomach, expression of sulfomucins and aberrant Lewis(a) (Le[a]) antigen is an excellent predictor of premalignant progression, and Helicobacter pylori infection is a crucial determinant for the development of atrophy, metaplasia, and adenocarcinoma. In the esophagus, the significance of sulfomucin expression is controversial, the aberrant expression of Le(a) has not been explored, and the role of H pylori in the evolution of preneoplastic conditions is unknown. We investigated in 155 patients referred for endoscopy the association of Barrett's esophagus with expression of sulfomucins, Lewis, secretor, and ABO phenotypes, and H pylori infection. We report a subtype of intestinal metaplasia, present in all patients with esophageal adenocarcinoma, similar to gastric intestinal metaplasia of colonic type (type III or incomplete), that expresses sulfomucins and aberrant Le(a) in goblet and columnar cells. Lewis(a+b-), nonsecretor and blood group A phenotypes, were all positively associated with esophageal adenocarcinoma, suggesting a genetic susceptibility. H pylori infection was detected in 75% of patients with esophageal adenocarcinoma.