Here, we report that in T cell acute lymphoblastic leukemia (T-ALL) the MYC oncogene controls the expression of TET1 and TET2 to maintain 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) patterns, which is associated with tumor cell-specific gene expression. This evidence concerns the gene TET2 and acute lymphoblastic leukemia.