Analysis of molecular mechanism of premalignant lesion of the stomach using genomic instability and new mucin gene.

1)高分化胃腺癌中基因组不稳定性（微卫星不稳定性，MSI）的频率较高。在伴有高分化腺癌的肠上皮化生组织中，MSI阳性率最高，MSI阳性腺癌中hMLH 1基因启动子区甲基化程度最高。MSI与DNA修复基因及其他相关基因甲基化的关系有待进一步研究。2）新的粘蛋白基因A3D4在胃腺癌肠上皮化生组织中表达。该产物对“正常”肠化病变为阴性。3）对肠化病变中的甲基化进行了系统的研究，发现许多基因表现出异常的甲基化模式，提示甲基化在胃癌癌前状态中的重要作用。

1) High frequency of the genomic instability (microsatellite instability, MSI) was found in well-differentiated adenocarcinoma of the stomach. Most of the intestinal metaplasia lesion which was accompanied with well-differentiated adenocarcinoma showed positivity for MSI.Moveover, hypermethylation of the promotor lesion of hMLH1 gene was observed in MSI-positive adenocarcinoma. Further study will be needed to analyze the association between MSI status and hypermethylation of the DNA repair genes and other related genes.2) New mucin gene A3D4 was expressed in the lesion of intestinal metaplasia of the adenocarcinoma of the stomach. This product was negative for "normal" intestinal metaplasia lesion.3) Methylation has systemically been investigated in the lesion of the intestinal metaplasia and many genes were found to show abnormal pattern of methylation, suggesting the important role of methylation to the premalignant status of the stomach cancer.