Helicobacter pylori and Gastric carcinoma: Effect on E-cadherin protein expression and E-cadherin gene promoter hypermethylation

Abstract

SUMMARY Objective: T he aim of this study was to investigate the aberrations in E- cadherin status in the gastric carcinoma patient's tissues and the adjacent non-cancerous tissues. The relationship between these aberrations and H. pylori infection as well as other important clinicopathological factors were assessed. Material and methods: This is a prorospective study includes 64 gastrectomy specimens from patients with gastric carcinoma. For each case, representive sections from the tumor tissue and the adjacent non-cancerous tissue were assessed for E-cadherin protein expression by immunohistochemistry and promoter methylation by the methylation-specific PCR analysis (MSP) technique. The results were correlated with H. pylori positivity and other clinicopathological variables. Results: • Reduced E-cadherin protein expression was detected in 28 cases (43.8%) whereas E-cadherin gene methylation was noted in 22 cases (34.4%) of the gastric carcinoma cases. • No significant association was detected between immunohistochemical expression and the methylation status of E-cadherin. • Gastric carcinoma with H.pylori infection in the adjacent tissues showed significantly higher frequency of E-cadherin methylation than H. pylori negative cases (P=0.01). • The frequencies of reduced E-cadherin expression and E-cadherin gene methylation were significantly higher in diffuse than intestinal type gastric carcinoma (P=0.02, P=0.01 respectively). • Neither the protein expression nor the metylation status of the E-cadherin, were significantly related to the pathological T stage or the nodal status of the studied patients. • E-cadherin gene methylation was observed in 10 of 20 cases with intestinal metaplasia (50%) and in 10 of 16 cases with dysplasia (62.5%).