中文摘要：

目的显微切割胃癌细胞检测染色体7q31.1区域的杂合性缺失（LOH）,绘制胃癌7q31.1区域等位基因缺失图谱,确定其常见最小缺失区域,揭示胃癌细胞的分子遗传学改变,分析7q31.1杂合性缺失与胃癌临床病理特征的关系。方法在胃癌组织石蜡切片上行显微切割获得胃癌细胞。采用Chelex-100方法分别抽提切割的胃癌细胞和相应正常对照细胞的DNA。利用高密度微卫星标志结合PCR技术,检测胃癌染色体7q31.1杂合性缺失,绘制胃癌染色体7q31.1等位基因的缺失图谱,确定其常见最小缺失区域。结果胃癌染色体7q31.1至少有一个位点存在杂合性缺失者21例,占70.0%（21/30）;D7S2459、D7S523、D7S2502、D7S486、D7S480、D7S650、D7S2486各位点杂合性缺失频率分别为10.0%、6.7%、23.3%、43.3%、26.7%、26.7%、20.0%;缺失图谱分析显示常见最小缺失区域位于D7S2502~D7S480之间。统计学分析表明这一区带微卫星位点的等位基因缺失阳性率与患者年龄、性别、原发灶位置、病理分期、分化程度以及淋巴结转移不相关（P〉0.05）。结论胃癌染色体7q31.1常见最小缺失区域在D7S2502~D7S480之间,在D7S486附近可能存在与胃癌相关的抑癌基因。

英文摘要：

Objective Through analyzing loss of heterozygosity（LOH） on chromosome 7q31.1 in human gastric carcinoma with microdissection,to construct allelic loss mappings and define the minimally lost regions（MLR） on chromosome 7q31.1,further explore the molecular genetics alteration during the malignant progression of human gastric mucosa and to analyze the relationships between LOH of chromosome 7q31.1 and clinicopathological parameters.Methods The gastric cancer cells were microdissected from paraffin sections.Sufficient and qualified DNA of microdissected cells and corresponding paired normal tissues were extracted by Chelex-100 method.Seven high dense microsatellite markers were used,combined with polymerase chain reaction（PCR）,to detect the frequencies of LOH of every selected microsatellite site on chromosome 7q31.1 in gastric carcinoma,then to map detailed alleic losses and define the minimally lost regions on chromosome 7q31.1.Results Frequency of LOH on chromosome 7q31.1 in gastric carcinoma tissues achieved 70.0%（21/30）;seven microsatellite markers′ frequencies of LOH were D7S2459 10.0%,D7S523 6.7%,D7S2502 23.3%,D7S486 43.3%,D7S480 26.7%,D7S650 26.7%,D7S2486 20.0% respectively.Through analyzing allelic loss mapping on chromosome 7q31.1,we had found that the MLR was between D7S2502 and D7S480.However there was no statistically significant correlation between the LOH at these loci and the clinical parameters such as age,sex,early or advanced stage,differentiation degree,primary position of gastric carcinomas,and lymphnode metastasis respectively（P〉0.05）.Conclusion The MLR on chromosome 7q31.1 in gastric carcinoma is at the region from D7S2502 to D7S480,which suggest that the region probably harbors a candidate tumor suppressor gene associated with human gastric carcinoma.