TET2 and leukemia: TET2 functions as a dioxygenase that converts 5 methylcytosine to 5 hydroxymethylcytosine, with a pivotal role in DNA demethylation.25 In mice, loss of TET2 has been shown to induce genome-wide enhancer methylation that in a CBF-AML model collaborates to induce an aggressive leukemia.26, 27 Further studies are needed to validate the very poor prognostic impact and define the pathogenetic/mechanistic basis of concomitant KIT-AL and TET2 mutations.