RUNX1 and acute lymphoblastic leukemia: RUNX1 plays a critical role during organogenesis, including definitive hematopoiesis(6) and skeletal development.(7, 8) A wide range of both germline and somatic RUNX1 genetic variants have been associated with various myeloid and lymphoblastic malignancies.(9) Genetic screening has revealed that RUNX1 is one of the most frequently altered genes in myelodysplastic syndromes (MDS)(10) and, when present in acute myeloid or lymphoblastic leukemia, is associated with an overall poorer prognosis.(11, 12)