Expression of polycomb protein EZH2 in multi-stage tissues of gastric carcinogenesis

OBJECTIVE: To study the role and significance of the polycomb group (PcG) protein EZH2 (enhancer of zeste homolog 2) in the multi-step process of intestinal-type gastric carcinogenesis. METHODS: Gastric specimens were obtained from 142 patients with gastric disease, including 34 with chronic non-atrophic gastritis (NCAG), 33 chronic atrophic gastritis (CAG) with intestinal metaplasia (IM), 40 CAG with dysplasia (DYS) and 35 with intestinal-type gastric carcinomas (GC), and 32 Helicobacter pylori-negative controls. The EZH2 protein was stained by the immunohistochemical method and was expressed as the intensity and percentage of the total number of epithelial cells. The chronic gastritis and the grading of dysplasia were classified according to Chinese National Consensus on chronic gastritis and the Padova international classification. RESULTS: The EZH2 protein levels in the specimens of normal gastric tissue, NCAG, CAG with IM, DYS and intestinal-type GC were gradually increased (P < 0.05), but statistical significance was not found between the groups of DYS and GC. CONCLUSION: PcG protein EZH2 plays an important role in the multi-step process of intestinal-type gastric carcinogenesis.