微卫星不稳定的胃癌中hMLH1的突变与甲基化
Mutation and methylation of hMLH1 in gastric carcinomas with microsatellite instability.
作者信息
Fang Dian-Chun, Wang Rong-Quan, Yang Shi-Ming, Yang Jian-Ming, Liu Hai-Feng, Peng Gui-Yong, Xiao Tian-Li, Luo Yuan-Hui
机构信息
Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
出版信息
World J Gastroenterol. 2003 Apr;9(4):655-9. doi: 10.3748/wjg.v9.i4.655.
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 methylation of hMLH1 promoter and MSI. Three mutations were found, two of them were caused by a single bp substitution and one was caused by a 2 bp 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 (>=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.
目的
评估胃癌中hMSH1的突变和甲基化与微卫星不稳定性（MSI）的相关性。
方法
采用二维电泳（Two-D）和DNA测序检测hMLH1的突变；用甲基化特异性PCR检测hMLH1启动子的甲基化；通过基于PCR的方法分析MSI。
结果
对68例散发性胃癌进行hMLH1启动子的突变、甲基化及MSI研究。发现3个突变，其中2个由单个碱基替换引起，1个由2个碱基替换引起，它们显示出相似的二维电泳条带模式。11例（16.2%）胃癌检测到hMLH1启动子甲基化。使用5个MSI标记，在17/68（25%）分析的肿瘤中至少1个位点检测到MSI。3个hMLH1突变均在MSI-H（≥2个位点，n = 8）中检测到，但在MSI-L（仅1个位点，n = 9）或MSS（无MSI或稳定的肿瘤，n = 51）中未发现突变。hMLH1在MSI-H中的甲基化频率（87.5%，7/8）显著高于MSI-L（11.1%，1/9）或MSS（5.9%，3/51）（P<0.01 - 0.001），但MSI-L和MSS之间无差异（P>0.05）。
结论
hMLH1的突变和甲基化均参与胃癌发生的MSI途径，但与LOH途径无关。
Zotero 插件