RESUMEN
<p><b>OBJECTIVE</b>To study COX-2 expression in H. pylori infected gastric mucosal epithelia and its significance in the carcinogenesis of the stomach.</p><p><b>METHODS</b>Rapid urease test and histological examination with basic magnenta staining were used to assess the status of H. pylori infection in the stomach. COX-2 was detected immunohistochemically.</p><p><b>RESULTS</b>COX-2 immunostaining was positive in 1 out of 12 cases with H. pylori-negative gastric mucosa and also in 1 out of 10 cases with H. pylori-positive gastric mucosa without macroscopic alterations, while COX-2 expression was found to be positive in 5 out of 9 cases with H. pylori related superficial gastritis with mucosal erosions. COX-2 expression was detected in 5 out of 10 cases with H. pylori-positive mild atrophic gastritis, 8 out of 10 cases with H. pylori-positive moderate-severe atrophic gastritis and intestinal metaplasia, and 6 out of 8 cases with H. pylori-positive moderate-severe dysplasia. COX-2 expression was positive in 22 out of 32 cases of gastric cancer.</p><p><b>CONCLUSION</b>H. pylori may induce COX-2 expression of gastric mucosal epithelia in chronic superficial gastritis, which is related to the development of mucosal injury. According to gastric mucosal carcinogenesis pattern up-regulation of COX-2 expression is associated with gastric mucosal carcinogenesis, and involved in the early development of premalignant lesions.</p>