9号染色体胃癌抑癌基因候选区域精细定位分析

Refined mapping analysis on candidate regions of tumor suppressor locus on chromosome 9 in gastric cancer

目的:通过对胃癌9号染色体微卫星位点杂合缺失进行精细定位,寻找新的胃癌相关抑癌基因。方法:选择在前期实验中筛选获得的9号染色体高频缺失位点D9S175附近10cm内加选的3个微卫星位点,采用PCR法对48例胃癌患者的肿瘤组织及癌旁正常组织进行PCR检测,使用自动荧光测序仪对产物进行杂合缺失分析。结果:9q21.1～21.2区域所测位点平均杂合缺失率为30%,其中以D9S237位点杂合缺失率最高(44%),D9S1879位点杂合缺失率最低(16%);微卫星位点D9S1122的杂合缺失率与肿瘤分化程度及淋巴结转移有关(P<0.05)。结论:9q21.1～21.2区域为高频杂合缺失区域,该区域内可能存在新的胃癌相关抑癌基因。

Objective：To screen the candidate tumor suppressor genes related to gastric cancer （GC） by refined mapping of loss of heterozygosity （LOH） of microsatellites on chromosome 9. Methods：Based on precious study we selected additional three microsatellites 10 cm distant from D9S175, a locus with high LOH frequency, on chromosome 9. The four refined fluorescence-labeled polymorphism markers were analyzed in the samples of GC tissues and adjacent normal tissues obtained from 48 GC patients （33 males and 15 females） by PCR method. The PCR products were electrophoresed for LOH scanning and analysis.Results：The average LOH frequency in the 9q21.1-21.2 region was 30%. The D9S237 locus had the highest LOH frequency of 44% and D9S1879 locus showed lowest LOH frequency of 16%. The LOH frequency of locus D9S1122 had correlation with the differentiation degree and lymphatic metastasis of GC （P〈0.05）. Conclusion：The 9q21.1-21.2 region has higher LOH frequency, in where candidate tumor suppressor gene（s） may exist.