结直肠锯齿状病变h-MLH1基因甲基化状态和蛋白表达意义研究  

Study of h-MLH1 gene promoter methylation and protein expression in colorectal serrated lesions

作　　者：葛畅[1] 王鲁平[1] 许春伟[1] 

机构地区：[1]北京军区总医院病理科,北京100700

出　　处：《中华肿瘤防治杂志》2014年第13期1022-1027,共6页Chinese Journal of Cancer Prevention and Treatment

基　　金：首都卫生发展科研专项基金(2011-5021-02)

摘　　要：目的:通过研究结直肠锯齿状病变组织中h-MLH1基因启动子区CpG岛甲基化及蛋白表达,探讨h-MLH1启动子甲基化状态与蛋白表达相关性及在锯齿状癌变通路中的作用,并分析h-MLH1基因在不同年龄层段甲基化程度。方法:收集北京军区总医院病理科2007-01-01-2012-12-31诊断为锯齿状病变标本225例,其中包括96例增生性息肉(hyperplastic polyp,HP)、61例广基(无蒂)锯齿状腺瘤/息肉(sessile serrated adenoma/polyp,SSA/P)和68例传统锯齿状腺瘤(traditional serrated adenoma,TSA);同时收集同院同期的54例管状腺瘤(tubular adenoma,TA)、69例结直肠癌(colorectal cancer,CRC)和42例正常结直肠黏膜组织作为对照。应用Taqman探针qPCR(MethyLight)方法检测各组织中h-MLH1基因CpG岛甲基化状态,同时采用免疫组织化学方法检测其蛋白表达水平,其中随机抽取锯齿状病变116例(HP 52例、SSA/P 41例、TSA 23例)、TA 20例、CRC 24例和正常结直肠黏膜组织24例,并将其甲基化状态与相应的蛋白表达水平及临床病理学资料进行统计学分析。结果:正常、TA、HP、SSA/P、TSA和CRC组织中,h-MLH1基因启动子CpG岛甲基化阳性表达率分别为9.24%(4/42)、40.74%(22/54)、22.92%(22/96)、45.90%(28/61)、61.76%(42/68)和52.17%(36/69)。HP组与正常、SSA/P、TSA及CRC组之间比较,正常组与SSA/P及TSA组之间比较,差异均有统计学意义,P<0.05;其余各组之间比较,差异均无统计学意义,P>0.05。正常、TA、HP、SSA/P、TSA和CRC组织中,h-MLH1蛋白阳性表达率分别为100%(24/24)、80.00%(16/20)、98.08%(51/52)、75.61%(31/41)、69.57%(16/23)和70.83%(17/24)。正常组与HP、SSA/P、TSA、TA、CRC组之间比较,差异均有统计学意义,P<0.05;其余各组之间比较,差异均无统计学意义,P>0.05。TA、SSA/P和TSA组中,h-MLH1基因甲基化与其蛋白表达差异均有统计学意义(P<0.05),且呈负相关,相关系数γ分别为-0.553、-0.497、和-0.473。TA、HP、SSA/P和TSA组中,h-MLH1基因�OBJECTIVE： Through detecting the promoter methylation and protein expression of h-MI.H1 gene in colorectal serrated lesions,to explore the relationship between them and its role in the serrated neoplasia pathway, and to analyze the methylation levels of different age stages. METHODS：A total of 225 cases diagnosed colorectal serrated lesions from Department of Pathology of Beiiing Military Region General Hospital during 2007-01-01 to 2012-12 31 were collect ed,which included 96 cases of HP,61 cases of SSA/P and 68 cases of TSA. 54 cases of tubular adenomas （TA） ,69 cases of CRC and 42 cses of normal colorectal mucosa were collected as control groups. CpG island methylation of h MLH1 gene promoter region was detected using Taqman probe qPCR （MethyLight）, while immunohistochemistry was used to detect expression of h-MLH1 protein from a random samples with 116 cases of serrated lesions （52 cases of HP,41 casesof SSA/P,23 cases of TSA）, 20 cases of TA, 24 cases of CRC and 24 cases of normal colorectal mucosa. Then we used statistical methods to analyze the methylation status, protein expression and clinicopathological data. RESULTS： Methylation rates of h-MLH 1 gene promoter in normal, TA, HP, SSA/P, TSA and CRC respectively were 9.24 % （4/42）, 40.74 （22/54）, 22.92% （22/96）, 45.90% （28/61）, 61.76 % （42/68） and 52.17% （36/69）. There were significant differences between HP and normal tissue,SSA/P,TSA,CRC,and between normal tissue and SSA/P,TSA（P〈0.05） ,while there weren＇t among the rest groups （P〈0.05）. The expression rates of h-MLH1 in normal group,TA, HP,SSA/P,TSA and CRC respectively were 100%（24/24）,80.00%（16/20）,98.08%（51/52）,75.61%（31/41）,69.57%（16/23） and 70.83% （17/24）. There were significant differences between normal group and HP, SSA/P, TSA, TA, CRC （P〈0.05）, while there were not among the rest groups （P〈0.05）. Methylation and protein expression of h-MLH1 had significant differences in TA,SSA/P and TSA group （P〈0.

关 键 词：结直肠肿瘤 锯齿状病变 基因 h-MLH1 DNA甲基化 免疫组织化学 

分 类 号：R735.34[医药卫生—肿瘤]