Mutation and methylation of hMLH1 in gastric carcinomas with microsatellite instability
Mutation and methylation of hMLH1 in gastric carcinomas with microsatellite instability
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DOI：
10.3748/wjg.v9.i4.655
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发表时间：
2003-04-01
影响因子：
4.3
通讯作者：
Luo, YH
中科院分区：
文献类型：
--
作者：
Fang, DC;Wang, RQ;Luo, YH
目的：目的：探讨胃癌组织中hMSH 1基因突变及甲基化与微卫星不稳定性（MSI）的关系。方法：采用双向电泳（Two-D）和DNA测序技术检测hMLH 1基因突变，甲基化特异性PCR检测hMLH 1基因启动子区甲基化，以PCR为基础的方法分析MSI。对68例散发性胃癌进行了hMLH 1基因启动子区突变、甲基化及MSI的研究。共发现3个突变，其中2个是由1个碱基替换引起的，1个是由2个碱基替换引起的，它们显示了相似的二维带型。11例（16.2%）胃癌组织hMLH 1基因启动子甲基化。通过使用五个MSI标记，在17/68（25%）的分析肿瘤中检测到至少一个位点的MSI。MSI-H（≥ 2个位点，n = 8）中检测到3个hMLH 1突变，而MSI-L（仅1个位点，n = 9）和MSS（无MSI或稳定的肿瘤，n = 51）中未检测到突变。MSI-H中hMLH 1的甲基化频率（87.5%，7/8）明显高于MSI-L组（11.1%，1/9）或MSS（5.9%，3/51）MSI-L组与MSS组比较差异有显著性（P < 0.01-0.001），但无统计学意义结论：hMLH 1基因突变和甲基化均参与了胃癌发生的MSI通路，但与洛缺失通路无关。
AIM: To appraise the correlation of mutation and methylation of hMSH1 with microsatellite instability (MSI) in gastric cancers.METHODS: Mutation of hMLH1 was detected by Two-dimensional electrophoresis (Two-D) and DNA sequencing; Methylation of hMLH1 promoter was measured with methylation-specific PCR; MSI was analyzed by PCR-based methods.RESULTS: Sixty-eight cases of sporadic gastric carcinoma were studied for mutation and methylatlon of hMLH1 promoter and MSI. Three mutations were found, two of them were caused by a single by substitution and one was caused by a 2 by substitution, which displayed similar Two-D band pattern. Methylation of hMLH1 promoter was detected in 11(16.2%) gastric cancer. By using five MSI markers, MSI in at least one locus was detected in 17/68(25%) of the tumors analyzed. Three hMLH1 mutations were all detected in MSI-H (greater than or equal to 2 loci, n = 8), but no mutation was found in MSI-L (only one locus, n = 9) or MSS (tumor lacking MSI or stable, n = 51). Methylation frequency of hMLH1 in MSI-H (87.5%, 7/8) was significantly higher than that in MSI-L (11.1%, 1/9) or MSS (5.9%, 3/51) (P < 0.01-0.001), but no difference was found between MSI-L and MSS (P > 0.05).CONCLUSION: Both mutation and methylation of hMLH1 are involved in the MSI pathway but not related to the LOH pathway in gastric carcinogenesis.