胃癌前病变不同阶段胃黏膜DNA甲基化表达分析及临床意义

目的探讨胃癌前病变不同阶段胃黏膜DNA甲基化表达差异及临床意义。方法选取2011年1月至2012年12月病理检查诊断为慢性萎缩性胃炎、肠上皮化生、轻．中度异型增生、重度异型增生、胃癌患者196例；另选择慢性浅表性胃炎患者55例（病理结果确诊为慢性浅表性胃炎，HP感染阴性）为对照。分别提取所有患者的DNA，酚／氯仿抽提法提取；采用甲基化特异聚合酶链反应（MSP）法检测胃黏膜组织c—myc，p16，hMLH1DNA甲基化表达并比较。结果慢性浅表性胃炎组均来发生p16甲基化、c-myc基因甲基化、hMLH1基因甲基化；随着病理严重程度的增加，p16甲基化、c-myc基因甲基化、hMLH1基因甲基化表达的病例数逐渐增多。胃癌组患者qp16甲基化、c—myc基因甲基化、hMLH1基因甲基化表达均为最高（P〈0．05）。结论随着病理严重程度的递增，各项DNA甲基化表达情况也逐渐增多，这对于胃癌的早期诊断、早期治疗、预后分析均有重要意义；且可以对胃癌前病变进行早期干预治疗，以及定期的随访观察，减少胃癌的发生。

Objective To explore the clinical significance of gastric mucosal DNA methylation expression at different stages of pathological changes before gastric carcinoma. Methods 196 patients who were diagnosed as chronic atrophic gastritis, intestinal metaplasia, mild to moderate dysplasia, severe dysplasia and gastric carcinoma by pathological examination from January 2011 to December 2011 in our hospital were selected as study group; other 55 cases of patients with chronic superficial gastritis （ pathological results diagnosed with chronic superficial gastritis, HP infection negative ） were chosen as control group. The DNA of all subjects were extracted respectively by phenol/chloroform extraction. The expression of c-myc, p16 and hMLH1DNA methylation in gastric mucosa was detected and compared by methylation specific polymerase chain reaction （MSP）. Results The p16 methylation, c - myc gene methylation and hMLH1 gene methylation were not detected in the chronic superficial gastritis group; and with the increase of pathological severity, the number of cases with p l 6 methylation, c - myc gene methylation and hMLH1 gene methylation gradually increased. The expression of P16 methylation,c-myc gene methylation and hMLH1 gene methylation were highest in gastric cancer group （ P〈0.05 ） . Conclusion With the increase of pathological severity, the DNA methylation expression is also gradually increased, for the analysis of the early diagnosis, early treatment and prognosis of gastric cancer has important significance. The early intervention treatment and regular follow-up observations can be used to treat precancerous lesions of gastric cancer and to reduce the occurrence of gastric cancer.