Fig. 1
From: Epigenetic regulation in the tumor microenvironment: molecular mechanisms and therapeutic targets

DNA methylation. DNA methylation is a dynamic process modulated by writers, erasers and readers. DNA methyltransferases (DNMTs) enzymes (“writers”) transfer a methyl group from S-adenosyl-L-methionine to the cytosine residue (5mC), including DNMT1, DNMT3A and DNMT3B. 5mC can be demethylated to 5-hydroxymethylcytosine (5hmC) via erasers. Indeed, 5hmC is iteratively oxidized to produce further oxidative derivatives, including 5-formylcytosine (5fC) and 5-carboxycytosine (5caC). The iterative oxidation reactions are performed by the ten-eleven translocation (TET1–3) family of proteins