中文摘要：

背景与目的：胃低分化腺癌癌变的分子机制至今不清楚,关键是未找到与胃低分化腺癌密切相关的基因.本研究拟建立胃低分化腺癌基因表达谱,筛选差异表达基因,进一步分析差异表达基因与胃癌发生、发展关系.方法：用含10 000个已知基因的cDNA微阵列分析胃低分化腺癌和癌旁正常胃黏膜基因表达谱的变化,免疫组化研究差异表达基因与胃癌的关系.结果：二倍以上的差异表达基因212个,其中在胃低分化腺中表达上调169个,表达下调43个.S-P免疫组化结果显示：EMS1蛋白表达定位于胞质,呈黄色至棕黄色;EMS1蛋白在20例正常胃黏膜阳性表达率为20%（4/20）,在146 例胃癌中阳性表达率为89.72% （131/146）;EMS1蛋白在胃癌中的表达高于正常胃黏膜（P＜0.001）.结论：发现EMS1与胃癌有关,为进一步寻找胃癌相关基因提供了重要的研究线索.

英文摘要：

Background and purpose： The molecular mechanism of the pathogenesis of poorly differentiated gastric carcinoma is unclear, because the key genes related to poorly differentiated gastric carcinoma have not been identified. The study was designed to establish the gene expression profile of poorly differentiated gastric carcinoma, isolate gastric carcinoma-related genes, and investigate the relationship between gastric carcinoma-related genes and gastric carcinoma. Methods： The changes of gene expression profile between poorly differentiated gastric carcinoma and adjacent normal tissue of gastric epithelia were analyzed by cDNA microarray which represented approximately 10 000 known genes that would be tested in the assay. Immunohistochemistry were employed to validate the relationship between gastric： carcinomaelated genes and gastric carcinoma. Results： 212 genes that were differentially expressed in cancer and non cancerous tissues were identified; 169 genes were highly expressed in cancer tissues by more than 2.0 fold, 43 genes were lower expressed in cancer tissues by more than 2.0 fold. EMSI protein was located in cytoplasma. The positive rate of EMSI protein expression was 20% （4/20） in normal gastric mucosa and 89.72% （131/146） in the gastric carcinoma, the difference was significant （P 〈 0. 001）. Conclusions： These results not only indicate that EMSI protein expression is related to carcinogenesis of gastric carcinoma, but also the technology is very useful for screening gastric cancer related genes.