Methylation and expression analysis of mismatch repair genes in extramammary Paget's disease
Methylation and expression analysis of mismatch repair genes in extramammary Paget's disease
复制标题
乳房外佩吉特病错配修复基因甲基化及表达分析
DOI：
10.1111/jdv.15404
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发表时间：
2019-05-01
影响因子：
9.2
通讯作者：
Guan, M.
中科院分区：
文献类型：
--
作者：
Kang, Z.;Zhu, Y.;Guan, M.
背景乳腺外佩吉特病（EMPD）是一种罕见的皮肤癌症，其生殖系和体细胞错配修复（MMR）基因突变的频率相对较高。然而，这些基因的甲基化和表达尚未在EMPD中得到证实。目的探讨MMR基因在EMPD中的甲基化和表达。方法采用免疫组化（IHC）染色检测和甲基化特异性PCR （MSP）检测57份EMMD样本中MLH1、MSH2、MSH6和PMS2蛋白的表达和启动子的甲基化情况，并利用pyrosequence检测MSH2启动子中高度甲基化的CpG位点。结果免疫组化检测显示，38.6%的EMPD患者MSH2表达降低，而所有肿瘤组织中MLH1、MSH6和PMS2表达正常。在MSH2的启动子中也发现了超甲基化，但在其他MMR基因中没有发现。对MSH2启动子的焦磷酸测序结果显示，CpG6（-87）和CpG3（-98）是最常见的两个甲基化CpG二核苷酸。MSH2表达降低与MSH2甲基化之间存在显著相关性。结论MSH2基因启动子表达降低和高甲基化是EMPD中常见的遗传变化，拓展了我们对MMR功能在该皮肤癌中的作用的认识。
Background Extramammary Paget's disease (EMPD) is a rare skin cancer with relative high frequencies of germline and somatic mismatch repair (MMR) genes mutations. However, the methylation and expression of these genes have not been validated in EMPD.Objective This study aims to confirm the methylation and expression of MMR genes in EMPD.Methods Immunohistochemical (IHC) staining detection and Methylation-specific PCR (MSP) were used to analyse MLH1, MSH2, MSH6 and PMS2 proteins' expression and promoters' methylation in 57 EMMD samples, and pyrosequence was used to find highly methylated CpG sites in MSH2 promoter.Results Immunohistochemical detection displayed reduced expression of MSH2 in 38.6% EMPD cases but normal expression of MLH1, MSH6 and PMS2 in all tumour tissues. Hypermethylation also was found in the promoter of MSH2 but not in other MMR genes. Pyrosequencing of MSH2 promoter showed CpG6 (-87) and CpG3 (-98) were the most common two methylated CpG dinucleotides. There is a significant correlation between reduced MSH2 expression and MSH2 methylation.Conclusion Reduced MSH2 expression and hypermethylation in this gene promoter were common genetic changes in EMPD, which expands our understanding of the role of MMR function in this skin cancer.