Bone marrow (BM) transduction and transplantation with FGFR1 fusion kinases can independently transform normal mouse [4–6] and human [7, 8] hematopoietic stem cells into leukemia cells, and suppression of FGFR1 activation using kinase inhibitors [9–11] can suppress leukemogenesis in humanized and syngeneic animal models, suggesting that this is the critical driver event in the disease. The gene discussed is FGFR1; the disease is leukemia.