Differential expression of manganese superoxide dismutase, copper/zinc superoxide dismutase, and catalase in gastric adenocarcinoma and normal gastric mucosa

Aims The biologic significance of antioxidant enzymes (AOEs) in gastric adenocarcinoma is still unclear. The aims of this study was to investigate the differential expression of AOEs in gastric carcinoma cells and non-cancerous counterparts and the relationship with the various clinicopathologic variables in gastric cancer patients. Methods Expression status of MnSOD, Cu/ZnSOD, and catalase was evaluated immunohistochemically in 120 paired gastric cancer and adjacent non-cancerous tissue. The tissues were fixed in absolute methanol immediately after surgical resection and immunohistochemistry was performed by microprobe system using tissuemicroarray slides. Results All AOEs revealed moderate to strong immunoreactivity in the parietal and intestinal metaplastic cells. Stromal cells in both cancer and non-cancerous tissue expressed MnSOD and catalase but Cu/ZnSOD. Immunoreactivity of MnSOD and catalase was increased in gastric carcinoma cells compared to their non-cancerous counterparts and revealed an association with intestinal type adenocarcinomas whereas immunoreactivity of Cu/ZnSOD did not reveal significant difference between cancer and non-cancerous mucosal cells. Conclusions Expression of MnSOD, Cu/ZnSOD, catalas in gastric cancer cells and non-cancerous counterparts was different and increased MnSOD and possibly catalase may in part be responsible for the increased risk of intestinal type adenocarcinoma of the stomach.