Although mutations in TET1 and TET3 have been observed in some hematological malignancies (like AML, T-ALL, and chronic lymphocytic leukemia (CLL) for TET1 and MDS, myeloproliferative neoplasms, CMML, and B-cell acute lymphoblastic leukemia (B-ALL) for TET3) and were reported to be enriched in relapsed B-ALL cases, TET1 and TET3 mutations are in general quite infrequent (150, 159, 160). The gene discussed is TET1; the disease is precursor B-cell acute lymphoblastic leukemia.