CBFs are often mutated in acute myeloid leukemia (AML), for example, in t(8;21) AMLs, characterized by expression of the AML1-ETO fusion gene, or inv(16) AMLs, delineated by the presence of the CBFβ-MYH11 (CM) event3. The gene discussed is RUNX1T1; the disease is acute myeloid leukemia.