TET2 and myeloid leukemia: Combined heterozygous loss of Tet2 (Tet2+/–) and Dnmt3a (Dnmt3a+/–) and expression of Flt3ITD/WT (Tet2+/– Dnmt3a+/– Flt3ITD/WT) results in an aggressive lethal myeloid leukemia.