Somatic mutations of RUNX1 are frequently found and have been intensively studied in hematological malignancies, such as acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), myelodysplastic syndromes (MDS), and chronic myelomonocytic leukemia (CMML). The gene discussed is RUNX1; the disease is chronic myelomonocytic leukemia.