Several fusion oncogenes showing a higher incidence in pediatric acute myeloid leukemia (AML) are associated with heterogeneous megakaryoblastic and other myeloid features. T. Mercher‘s team, in collaboration with F. Pflumio’s, studied how developmental mechanisms influence human leukemogenesis by ETO2::GLIS2, associated with a poor prognosis. They highlighted the role of cytokines in the permissiveness of leukemic transformation by oncogenic ETO2::GLIS2 fusion of hematopoietic cells during development, and suggested new therapeutic avenues.