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].