In the myeloid lineage, epigenetic modifiers, including Tet methylcytosine dioxygenase 2 (TET2), isocitrate dehydrogenase 1 (IDH1), IDH2, enhancer of zeste homologue 2 (EZH2) are mutated and lead to defects in DNA and/or histone epigenetic modifications in several myeloid malignancies, such as chronic myeloid leukemia (CML) and acute myeloid leukemia (AML) (129, 130). The gene discussed is TET2; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.