中文摘要：

肿瘤的发生、发展与表观遗传异常改变密切相关，其中5-胞嘧啶碱基甲基化（5-mC）和RNA的N6-甲基腺苷（m-6-A）是常见并极其重要的表观改变，具有高度保守性，几乎存在于所有生物体中，参与调控基因组稳定和表达，在分化发育和生殖过程中起有重要作用。研究发现DNA和RNA的高甲基化表观修饰在恶性肿瘤的发生、发展和侵袭转移中起重要作用。但这一过程可被一些去甲基化酶逆转，其中DNA去甲基化酶TET（ten-eleven translocation）酶家族和异柠檬酸脱氢酶（IDH）可催化5-mC成为5-羟甲基胞嘧啶，而RNA去甲基化酶肥胖风险基因和ALKBH5可逆转RNA的m-6-A修饰。本文综述DNA与RNA甲基化的生物学特征和机制及其在肿瘤中功能的研究进展。

英文摘要：

Tumor development is closely related to abnormal epigenetic changes. The 5 position of cytosine （5-mC） and RNA N6-methyladenosine （m-6-A）, which exist in almost all organisms and highly conserved, are common and extremely important epigenetic change in the regulation of genomic stability, gene expression, differentiation, development and reproductive. The study has shown that aberrant epigenetic alterations, including DNA and RNA hypermethylated modification, played an important role in the invasion and metastasis of malignant tumor. However, it can be reversed by some dehydrogenase, such as ten-eleven translocation （TET） family and isocitrate dehydrogenase （IDH） which may convert 5-mC to 5-hydroxymethylcytosine （5-hmC）, and RNA demethylase obesity risk gene, fat mass and obesity-associated enzyme and ALKBH5 can reverse m-6-A of RNA. This paper reviews the biological characteristics and mechanisms of DNA and RNA methylation as well as their function in tumor development.