We analyzed the activities of developmental TFs encoded by TALE homeobox genes (IRX1 and MEIS1), NKL homeobox genes (HLX and MSX1), ETS genes (ERG, ETS2, and SPIB), and T-box genes (EOMES and TBX21), using suitable BCP-ALL-derived cell lines. The gene discussed is MEIS1; the disease is acute lymphoblastic leukemia.