中文摘要：

5-羟甲基胞嘧啶（5hmC）是新发现的一种的修饰碱基,以低水平存在于哺乳动物的多种细胞类型中。5hmC是10-11易位（TET）家族的酶通过氧化5-甲基胞嘧啶（5mC）产生的。5hmC不仅能够降低MeCP蛋白的甲基化结合结构域（MBD）与甲基化DNA的亲和性,具有潜在的参与基因表达调控的转录调节功能,而且参与了DNA去甲基化过程。因此关于5hmC的研究日益受到学者们的青睐,随着5hmC甲基化分析和检测方法学日益发展,发现5hmC分布具有组织特异性,并且5hmC在肿瘤组织中含量显著降低,可能成为某些肿瘤早期诊断的分子标志物。

英文摘要：

5-hydroxymethylcytosine（5hmC） is a new modified base,and presents at low levels in diverse cell types in mammals.5hmC is generated by the TET（ten-eleven translocation,TET） family of enzymes through oxidation of 5-methylcytosine（5mC）.5hmC can decrease the affiliation between the methyl-CpG binding domain（MBD） of methylcytosine binding proteins（MeCP） and methlated DNA,revealing it has the potential function of epigenetic gene regulation.5hmC also has been proposed as a potential intermediate in active DNA demethylation.Therefore,5hmC has attracted increasing attention from researchers and more techniques and methods are used to detect 5hmC.Studies report that 5hmC differes in different tissues and is significantly decreased in tumor tissues,which suggest it may be used as a useful molecular marker for tumor diagnosis.