Expression of claudin-4 and b-catenin in gastric premalignant lesions

Background and study aims : Abnormal expression of claudin-4 and b-catenin play a role in carcinogenesis. The purpose of the present study was to examine claudin-4 and b-catenin expression in normal and precancerous gastric mucosa. Patients and methods : Endoscopic biopsy specimens [normal gastric mucosa (n = 22), intestinal metaplasia (n = 24), dysplasia (n = 18), Helicobacter pylori (H. pylori)-associated chronic gastritis (n=32) and remnant gastric mucosa (n=18)] obtained from different 114 patients were examined by immunohistochemistry. Results : Claudin-4 expression was present in 94.4% of dyspla- sia, 87.5% of intestinal metaplasia, 62.5% H. pylori-associated chronic gastritis, and 88.9% remnant gastric mucosa but only 18.2% of normal gastric mucosa biopsies. Decreased expression of b-catenin was present in 27.8% of dysplasia, 8.3% of intestinal metaplasia, 15.6% of H. pylori-associated chronic gastritis, and 22.2% of remnant gastric mucosa biopsies, but was not present in normal gastric mucosa. When compared with normal gastric mucosa, there was a significant difference in claudin-4 expression in all groups (P < 0.05), but a significant difference was detected in dysplasia and remnant gastric mucosa for b-catenin (P < 0.05). Conclusions : Our results suggest that claudin-4 expression is upregulated in premalignant gastric alterations. (Acta gastro- enterol. belg., 2009, 72, 407-412).