CBF mutations in AML are cytogenetically characterized by t (8; 21) or inv (16)/t (16; 16), producing RUNX1-RUNX1T1 (AML1-ETO) or CFB β subunit-myosin heavy chain 11 (CBFβ-MYH11) fusion proteins, respectively (28). The gene discussed is RUNX1T1; the disease is acute myeloid leukemia.