胃癌微卫星不稳定与hMLH1蛋白表达缺失的相关性研究  

Microsatellite instability and loss of hMLH1 protein expression in gastric carcinoma tissues

作　　者：郭新海 毛芙敏 吴旭辉 许敬 凌志强[2] 

机构地区：[1]舟山市舟山医院肿瘤科,浙江舟山316000 [2]浙江省肿瘤医院浙江省肿瘤研究所,浙江杭州310002

出　　处：《中华肿瘤防治杂志》2012年第12期892-895,共4页Chinese Journal of Cancer Prevention and Treatment

基　　金：浙江省自然科学基金(Y204167)

摘　　要：目的:分析胃癌组织微卫星不稳定性、hMLH1蛋白表达以及两者的关系。方法:选取65例胃癌组织标本,常规酚-氯仿法提取DNA,选取基因组上的五个微卫星位点BAT26、BAT25、D5S346、D2S123和D17S250,进行PCR扩增,扩增产物加入GeneScan 500size standard共同热变性后,用60g/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5个微卫星位点如出现≥2个位点的不稳定,定为微卫星的高度不稳定(MSI-H),1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蛋白的表达。结果65例胃癌组织中,有21例(32.3%)表现为MSI-H,20例(30.8%)有hMLH1蛋白表达的缺失。在21例MSI-H的胃癌组织中,18例(85.7%)有hMLH1蛋白表达的缺失。44例MSI-L/MSS的胃癌组织中仅2例(4.5%)有hMLH1表达的缺失。胃癌的MSI-H与hMLH1蛋白表达的缺失高度相关,P<0.01。其中,25例高分化腺癌有7例(28.0%)表现为MSI-H,6例(24.0%)有hMLH1表达的缺失;40例中低分化腺癌14例(35.0%)表现为MSI-H,12例(30.0%)有hMLH1蛋白表达的缺失。26例早期癌有1例(3.8%)表现为MSI-H,2例(7.7%)有hMLH1蛋白表达的缺失;39例中晚期癌20例(51.3%)表现为MSI-H,17例(43.6%)有hMLH1蛋白表达的缺失。微卫星不稳定在中晚期胃癌明显高于早期胃癌(P<0.01),但在不同分化程度的胃癌间差异无统计学意义;hMLH1蛋白表达缺失与分化程度无关,但在早期与中晚期的胃癌间差异有统计学意义,P<0.05。结论:由hMLH1基因所致细胞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着肿瘤的演进而增加。[ABSTRACT] OBJECTIVE： To detect the microsatellite instability （MSI） and expression of hMLH1 gene in gastric cancinoma tissues, and explore the molecular biological mechanism underlying the carcinogenesis of gastric cancinoma. METHODS= A total of 65 cases of gastric cancinomas tissues from surgical excision samples were collected. The microsat- ellite locus of BAT-26, BAT25, D5S346 ,D2S123 and D17S250 were amplified by PCR after DNA abstraction. Then PCR products were mixed together with GeneScan 500 size standard followed by heat denaturation. Microsatellites were ana- lyzed by capillary electrophoresis with 60 g/L SLPA and 8 mol/L 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 hMLH1 gene hMLH1 was detected by immunohistoehimical staining. RESULTS= Of the 65 cases of gastric carcinomas, 21 cases（32. 3%） showed MSI-H and 20 cases（30.8%） showed loss of hMLH1. In the 21 cases of the MSI,18 eases（85.7%） were accom- panied by loss of hMLH1 expression,whereas in the 44 cases of the MSI-L/MSS,only 2 cases（4.5 %） were accompanied by loss of hMLH1 expression. MSI was significantly related with hMLH1 deficiency （P〈0.01）. Of the 25 cases of well- differentiated carcinomas,7 cases（28.0%） manifested MSI-H and 6 cases（24.0%） showed protein defection of hMLH1. Comparatively,14 cases （35.0%） manifested MSI-H and 12 cases （30.0%） showed protein defection of hMLH1 in40 cases poorly-differentiated carcinomas. Of the 26 cases early stage carcinomas,only 1 cases（3.8%） manifested MSI-H and 2 cases（7. 7G） showed protein defection of hMLH1, whereas 20 cases （51. 3G） manifested MSI-H and 17 cases （43.6%） showed protein defection of hMLH1 in 39 cases advanced carcinomas. The MSI frequency was higher in ad- vanced stage than that in early stage of gastri

关 键 词：胃肿瘤 微卫星不稳定性 HMLH1蛋白 

分 类 号：R735.2[医药卫生—肿瘤]