TET2 and myelodysplastic syndrome: In a range of myeloid and lymphoid neoplasms, the frequencies of TET2 mutations are 20–35% in myelodysplastic syndrome (MDS) (26), 30–60% in chronic myelomonocytic leukemia (CMML) (27), 12–34% in acute myeloid leukemia (AML) (28) and 2–33% in lymphoid malignancies (5) (Figure 3).