TET1 and acute lymphoblastic leukemia: AML carries RUNX1–RUNX1T1 (transcription factor involved in the differentiation of hematopoietic stem cells into adult blood cells) fusion genes with functional deficiency in TET2 and DNMT3A genes [219], while TET1 is highly sensitive to PARP1 inhibitors in ALL patients, as shown in different clinical studies [206].