Abstract: Epigenetics is a heritable alteration of the genetic function without an alteration in DNA sequence. Methylation is one of the most cardinal forms of epigenetic modification, which is a tie between genotype and phenotype. Under the regulation of DNA methyltransferases, DNA methylation hands down by heredity during the proliferation and differentiation of cells. The difference of DNA methylation in eukaryote plays a significant role in the regulation of gene expression in different ways. Nowadays, with the help of the development in the research technique of DNA methylation, humans are manding the pace in exploring DNA methylation. Pleasant progress has come out especially in the research of some diseases such as cancer. Actually, DNA methylation has become a hotspot in the field of Biology.

Key words: DNA methylation, Gene expression, Neoplasms, Stem cells