These results suggested that both CBFβ-SMMHC and CBFβ-SMMHC-ΔHABD increased RUNX1 DNA binding in hematopoietic cells, and that binding of RUNX1/CBFβ-SMMHC to DNA and direct transcription regulation are critical for CBFβ-SMMHC to induce leukemia. Here, RUNX1 is linked to leukemia.