TET2, a member of the ten-eleven-translocation (TET) family of genes, is a methylcytosine dioxygenase that catalyzes the conversion of methylcytosine to 5-hydroxymethylcytosine. It is a candidate tumor suppressor gene reported to be mutated in approximately 14 % of patients with JAK2V617F-positive myeloproliferative neoplasms, and can be mutated in other hematopoietic disorders such as myelodysplastic syndromes, acute myeloid leukemia, and chronic myelomonocytic leukemia. Analysis of the TET2 and JAK2 mutations in these neoplasms suggests that mutations in TET2 do not represent a predisposition for acquiring mutations in JAK2.Synonyms: KIAA1546, Methylcytosine dioxygenase TET2