MA9.3ITD (MLL-AF9 fusion gene plus FLT3-ITD mutation; MLL, also known as KMT2A) and MA9.3RAS (MLL-AF9 fusion gene plus NRASG12D mutation) were established by Dr. James Mulloy and cultured in IMDM supplemented with 20% FBS.21 (link) MONOMAC 6, MV4-11, MOLM13, Kasumi-1, THP-1, SKNO-1 and ML-2 are obtained and maintained as previously described.22 (link) Homoharringtonine purchased from Sigma-Aldrich was used in this study.