However, NPM1 mutation is considered to be a driver mutation and a major gene causing leukemogenesis by the scientific community, probably due to its leading role and tight connection with AML pathogenesis [3,4,7,12], even though it does not completely fulfill the strict definition of initiating AML alone in the mouse models, having a strong influence on and collaborating with MEIS1 overexpression to induce leukemia [36]. The gene discussed is MEIS1; the disease is acute myeloid leukemia.