Evidence that the GFI1B expression level may be linked to leukemia comes from experiments showing that forced expression of GFI1B inhibited IL-6-induced cell cycle arrest and differentiation in the murine myeloblastic leukemia cell line M1 (67) and resulted in expansion of immature erythroblasts and repression of myeloid in human primary hematopoietic progenitors (57). This evidence concerns the gene GFI1B and leukemia.