非乳腺 Paget 病中错配修复基因的甲基化和表达分析。

Methylation and expression analysis of mismatch repair genes in extramammary Paget's disease.

机构信息

Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, P. R. China.

Department of Pathology, Huashan Hospital North, Fudan University, Shanghai, P. R. China.

出版信息

J Eur Acad Dermatol Venereol. 2019 May;33(5):874-879. doi: 10.1111/jdv.15404. Epub 2019 Feb 19.

DOI:10.1111/jdv.15404

PMID:30784122

Abstract

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 pyro-sequence 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.

摘要

背景

派杰氏病（EMPD）是一种罕见的皮肤癌，其种系和体细胞错配修复（MMR）基因突变频率相对较高。然而，这些基因的甲基化和表达尚未在 EMPD 中得到验证。

目的

本研究旨在确认 EMPD 中 MMR 基因的甲基化和表达。

方法

采用免疫组织化学（IHC）染色检测和甲基化特异性 PCR（MSP）分析 57 例 EMPD 样本中 MLH1、MSH2、MSH6 和 PMS2 蛋白的表达和启动子甲基化情况，焦磷酸测序寻找 MSH2 启动子中高度甲基化的 CpG 位点。

结果

IHC 检测显示 38.6%的 EMPD 病例中 MSH2 表达降低，但所有肿瘤组织中 MLH1、MSH6 和 PMS2 表达正常。MSH2 启动子也存在异常甲基化，但其他 MMR 基因无此现象。MSH2 启动子的焦磷酸测序显示 CpG6（-87）和 CpG3（-98）是最常见的两种甲基化 CpG 二核苷酸。MSH2 表达降低与 MSH2 甲基化之间存在显著相关性。