Given our observation that TET2 silencing in primary and cultured T-ALL cells was associated with TET2 promoter methylation (Fig. 1 G and H), we next tested the ability of the Food and Drug Administration–approved DNA demethylating agent, 5-aza, to rescue TET2 gene expression in T-ALL as an alternative therapeutic approach. This evidence concerns the gene TET2 and acute lymphoblastic leukemia.