The Expression And Signification Of DNA Mismatch Repair Gene HMLH1 In Gastric Cancer And Premalignant Lesions

Objective: To detect the expression of DNA mismatch repair genehMLH1 in gastric cancer and premalignant lesions and to analyze itassociated with clinical patho- parameters in gastric cancer, and to study therelation between expression of hMLH1 and development of gastric cancer, inorder to explore the molecular mechanism in cancer development, we hopethat it can give help on early diagnosis, prophylaxis and treatment of gastriccancer.Methods: Immunohistochemical technique was used to detecthMLH1 protein of 40 cases of gastritis (chronic superficial gastritis andchronic atrophic gastritis with intestinal metaplasia were 20 cases,respectively), 8 cases of gastric adenomatous polyp, 58 cases of gastriccancer and corresponding adjacent cancer. Statistical analysis was used by x~2test and Pearson's correlation.Results: The hMLH1 protein was mostly expressed in epithelialcytoplasm, a little in cell nucleus. The positive expression rates of hMLH1 inchronic gastritis, gastric adenomatous polyp, corresponding adjacent cancerand gastric cancer were 90%, 62.5%, 62.1% and 72.4%, respectively, therewere significantly different among them (P＜0.05). The positive expressionrates of hMLH1 in chronic gastritis were significantly higher than that ingastric adenomatous polyp, corresponding adjacent cancer and gastric cancer,respectively, there were statistically significant (P＜0.05), the positiveexpression rates of hMLH1 in the latter three groups were not significantly different (P＞0.05). In 58 cases of adjacent neoplastic mucosa, including 21cases of chronic superficial gastritis and 37 cases of chronic atrophic gastritiswith intestinal metaplasia, the positive expression rates of hMLH1 betweenchronic superficial gastritis of adjacent cancer and chronic atrophic gastritiswith intestinal metaplasia of adjacent cancer were 57.1% and 64.9%, therewere not significantly different (P＞0.05). The positive expression rates ofhMLH1 in chronic superficial gastritis of non-tumor (90%) were obviouslyhigher than that in chronic superficial gastritis of adjacent cancer, and thepositive expression rates of hMLH1 in chronic atrophic gastritis withintestinal metaplasia of non-tumor (90%) were obviously higher than that inchronic atrophic gastritis with intestinal metaplasia of adjacent cancer, therewere obvoirsly different (P＜0.05), respectively. There were not correlatedbetween absence of mismatch repair gene hMLH1 expression in gastriccancer and corresponding adjacent cancer. The positive expression ofhMLH1 in gastric cancer was not associated with age, gender, the site oftumor, metastasis of Lymph node and clinical patho-stages (P＞0.05).Conclusion: Absence of mismatch repair gene hMLH1 expressionmay be one of the early molecule events of gastric cancer, and it may be thebase of carcinogenesis of gastric cancer; timely visiting and monitoringchronic gastric patients with absence of the expression of hMLH1 proteinmay contribute to early diagnosis of gastric cancer.