Lethally irradiated mice transplanted with MLL-ENL immortalized bone marrow progenitors develop AML following a latency period of an average of 90–100 days, with leukaemic cells expressing the myeloid surface markers Mac-1 and Gr-1 as well as Lmo2. 28 We hypothesized that maintenance of high Lmo2 levels could be important for the ability of these cells to cause AML in vivo. The gene discussed is KMT2A; the disease is acute myeloid leukemia.