中文摘要：

目的：筛选并系统分析由DNA甲基化介导的乳腺癌致病基因。方法本研究利用国际癌症基因组计划提供的表观基因组数据，通过生物信息学方法筛选并系统分析了乳腺癌中异常表达的基因及其表观遗传调控机制。结果通过t检验筛选了428个乳腺癌异常表达的基因，功能富集分析揭示乳腺癌中上调的基因与细胞周期密切相关，而下调的基因则显著富集在激素反应相关的功能上。对DNA甲基化组的研究揭示乳腺癌呈现了独特的DNA甲基化模式，并筛选到23个由DNA甲基化异常介导的乳腺癌致病基因。结论 DNA甲基化可介导乳腺癌致病基因的异常表达，是乳腺癌早期诊断和预后的重要生物标记。

英文摘要：

Objective To identify and analyze the DNA methylation induced pathogenic genes in breast cancer.Methods Using genomic data provided by the international cancer genome,we carried out systematic a-nalysis of the abnormal gene expression in breast cancer and epigenetic regulation mechanism by bioinformatics methods.Results We identified 428 genes with abnormal expressions in breast cancer by t test.Functional enrich-ment analysis revealed genes up-regulation in breast cancer were closely related to the cell cycle,and those down-regulated were significantly enriched in the hormone response function.Study on DNA methylation revealed that breast cancer showed an unique DNA methylation pattern.Further analysis reveals 23 breast cancer genes induced by abnormal DNA methylation.Conclusion DNA methylation can mediate the abnormal expression of breast canc-er genes,and is an important biological marker for early diagnosis and prognosis of breast cancer.