In order to study AML1/ETO’s role in preleukemia, we exploited a murine immortalized pluripotent hematopoietic stem/progenitor (HSPC) cell line, EML C1 (referred to as EML from here on), which can be induced to differentiate into both the lymphoid and myeloid lineages upon appropriate cytokine treatment14. The gene discussed is RUNX1; the disease is myelodysplastic syndrome.