胃癌微卫星不稳定与错配修复蛋白表达的缺失  

Microsatellite instability and loss of mismatch-repair protein expression in gastric carcinoma

作　　者：李建华[1] 石先哲[2] 吕申[1] 刘敏[1] 王朝晖[1] 刘丽娜[3] 姜静[4] 许国旺[2] 

机构地区：[1]大连医科大学附属第二医院实验中心,辽宁省大连市116023 [2]中国科学院大连化学物理研究所国家色谱研究分析中心,辽宁省大连市116011 [3]大连医科大学附属第一医院消化内科,辽宁省大连市116001 [4]大连理工大学材料系,辽宁省大连市116023

出　　处：《世界华人消化杂志》2004年第8期1774-1777,共4页World Chinese Journal of Digestology

基　　金：中国科学院知识创新工程领域前沿资助项目;No.DICPK2001A4~~

摘　　要：目的:分析胃癌组织微卫星不稳定性、错配修复蛋白表达以及二者的关系,探讨胃癌发生的分子生物学机制. 方法:胃腺癌及癌旁组织标本56例,高分化癌22例,中低分化癌34例,早期癌20例,中晚期癌36例,常规酚-氯仿法提取DNA,选取基因组上的五个微卫星位点BAT-26、D17S261、D3S1283、D2S123和D3S1611, 进行PCR扩增,扩增产物加入GeneScan 500 size stan- dard共同热变性后,用60 g/L的SLPA添加8mol/L尿素做筛分递质的毛细管电泳进行分析.被检测的五个微卫星位点如出现两个或两个以上位点的不稳定,定为微卫星的高度不稳定(MSI-H),一个位点出现不稳定、定为微卫星的低度不稳定(MSI-L),没有位点出现不稳定、定为微卫星稳定(MSS).石蜡切片常规免疫组织化学SP方法检测hMLH1和hMSH2蛋白的表达,肿瘤组织上皮细胞核不着色,而周围组织上皮细胞核着色判定为hMLH1或hMSH2 蛋白表达的缺失. 结果:在56例胃腺癌中,有14例(25%)表现为MSI-H, 14例(25%)有错配修复蛋白表达的缺失.在14例MSI-H的胃癌组织中,11例(79%)有hMLH1或hMSH2表达的缺失,42例MSI-L/MSS的胃癌组织仅3例(7%)有hMLH1 或hMSH2表达的缺失.胃癌的MSI-H与错配修复蛋白表达的缺失高度相关(P<0.01).其中的22例高分化腺癌有7例(32%)表现为MSI-H、6例(27%)有错配修复蛋白表达的缺失,34例中低分化腺癌7例(21%)表现为MSI-H、8例(24%)有错配修复蛋白表达的缺失,20例早期腺癌有1例(5%)表现为MSI-H、3例(15%)有错配修复蛋白表达的缺失,36例中晚期腺癌13例(36%)表现为MSI-H、11例(31%)有错配修复蛋白表达的缺失.微卫星不稳定性在中晚期胃癌明显高于早期胃癌(P<0.05),但在不同分化程度的胃癌差异不明显;MMR蛋白表达缺失在高分化与低分化以及早期与中晚期的胃癌均无显著性差异. 结论:细胞错配修复功能缺陷与部分胃癌的发生有关,而与胃癌的生物学行为无关;胃癌的微卫星不稳定性随AIM: To detect the microsatellite instability (MSI) and expression of mismatch repair (MMR) gene in gastric cancinoma, and to explore the molecular biological mechanism underlying the carcinogenesis of gastric cancinoma. METHODS: A total of 56 cases of gastric cancinomas and surrounding non-cancerous tissues from surgical excision samples were collected, among which 22 cases were well and 34 cases were poorly differentiated adenocarcinoma, 20 cases were in early stage and 36 cases were in advanced stage of the disease. The microsatellite locus of BAT-26, D17S261, D3S1283, D2S123 and D3S1611 were amplified by PCR after DNA abstraction. Then PCR products were mixed together with GeneScan 500 size standard followed by heat denaturation. Microsatellites were analyzed by capillary electrophoresis with 6% SLPA and 8 moL/L-1 urea as sieving medium. Carcinoma were characterized as high MSI (MSI-H) if they manifested instability at two or more markers, low MSI (MSI-L) if unstable at only one marker, and microsatellite stable (MSS) if they showed no instability at any marker. Expression of MMR gene hMLH1 and hMSH2 were detected by immunohistochimical staining using the streptavidin-biotin-peroxidase complex method with 3, 3'-diaminobenzidine as chromogen. RESULTS: Of the 56 cases of gastric carcinomas, 14 cases (25%) showed MSI-H and 14 cases (25%) showed loss of MMR. In the 14 cases of the MSI, 11 cases (79%) were accompanied by loss of hMLHl/hMSH2 expression, whereas In the 42 cases of the MSI-L/MSS, only 3 cases (7%) were accompanied by loss of hMLHl/hMSH2 expression. MSI was significantly related with mismatch repair deficiency (P <0.01). Of the 22 cases of well-differentiated carcinomas, 7 cases (32%) manifested MSI-H and 6 (27%) cases showed protein defection of MMR, Comparatively, 7 cases (21%) manifested MSI-H and 8 cases (24%) showed protein defection of MMR in 34 cases poorly-differentiated carcinomas. Of the 20 cases early stage carcinomas, only 1 cases (5%) manifested MSI-H and 3 (15%) cases showed protein defe

关 键 词：错配修复蛋白 表达 胃癌组织 MSI 微卫星不稳定性 中晚期 腺癌 高分 缺失 结论 

分 类 号：R735.2[医药卫生—肿瘤]