Expression of claudin-4 and beta-catenin in gastric premalignant lesions.

Background and study aims: Abnormal expression of claudin-4 and β-catenin play a role in carcinogenesis. The purpose of the present study was to examine claudin-4 and β-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 dysplasia, 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 β-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 β-catenin (P < 0.05). Conclusions: Our results suggest that claudin-4 expression is upregulated in premalignant gastric alterations.