Analyses revealed that mutation or deficiency of TET2 occurred in ~15% of patients with myeloid cancers, including myelodysplastic syndrome (MDS), myeloproliferative disorders, and AML.86 In patients with CML, mutation of TET2 has been detected in ~50% of patients.87 Although TET2 mutations have been found in several myeloid malignancies, their prognostic effect remains controversial. The gene discussed is TET2; the disease is myelodysplastic syndrome.