RUNX1 and acute myeloid leukemia: Therefore, it is clear that RUNX1-RUNX1T1 blocks the regulatory function of RUNX1 by competing with it at its binding sites, and the displacement of RUNX1 with RUNX1-RUNX1T1 at P2 is crucial for the downregulation of UBXN8 in t(8;21) AML cells.