To investigate the possibility of a direct link between MLL-fusion activation of HOXA genes and activity of the LMO2 +1 enhancer in AML leukaemic cells, we took advantage of a mouse cellular model where bone marrow progenitors are immortalized with the fusion protein MLL-ENL.28 These cells generate AML in vivo when transplanted into lethally irradiated congenic recipients and upregulate expression of Hox genes.29 Here, LMO2 is linked to acute myeloid leukemia.