RUNX1 ETO tetramerization-IN-1 is a small-molecule inhibitor that specifically targets NHR2 of RUNX1 ETO, effectively inhibiting the tetramerization process. With an EC50 value of 0.25 μM, this compound successfully restores gene expression that has been down-regulated by RUNX1 ETO. Furthermore, RUNX1 ETO tetramerization-IN-1 demonstrates promising anti-leukemic activity by inhibiting the proliferation of SKNO-1 cells dependent on RUNX1 ETO and significantly reducing RUNX1 ETO-associated tumor growth in a mouse model [1] [2] [3].