Expression of Cyclooxygenase-2 Protein in Gastric Carcinogenesis.

PURPOSE: The increased expression of cyclooxygenase (COX)-2 has been implicated in the development and progression of human cancers. We investigated COX-2 expression in normal, gastric adenomas and adenocarcinomas.
MATERIALS AND METHODS: COX-2 protein was assayed in gastrectomy and biopsy specimens, from 68 gastric adenocarcinomas, 40 gastric adenomas and 35 normal gastric tissues, by immunohistochemistry, and 32 specimens of normal and adenocarcinomas by western blot analysis. Correlation between COX-2 expression and various clinicopathological factors were studied in the gastric adenocarcinoma.
RESULTS: COX-2 protein expression in epithelial cells was increased in 6/40 (15%) of the adenomas and 55/68 (80.9 %) of the adenocarcinomas, while normal mucosa was not expressed. COX-2 expression was increased in differ-entiated gastric carcinomas compared with those in the undifferentiated group (p<0.05). The expression of COX-2 protein was unrelated to tumor size, depth of tumor invasion and the presence of lymphatic or vascular invasions. Western blot analysis showed the enhanced expression of the COX-2 protein (23 out of 32)(71%) in gastric carcinomas compared to that of normal gastric mucosal epithelium.
CONCLUSION: The above results indicated that the expression of COX-2 protein occurs in dysplastic epithelium and gastric carcinomas, which suggests COX-2 expression may contribute to tumor formation.