TET1 is an MLL partner in cases of acute myeloid (AML) and lymphoid (ALL) leukemias, while loss of function of TET2 is strongly associated with myelodysplastic syndromes, myeloproliferative neoplasms, and myeloid leukemias (Ko et al., 2010). This evidence concerns the gene KMT2A and acute myeloid leukemia.