text:  MLL-ENL-ERtm bone marrow, transition, biological rep 1 MLL-ENL-ERtm bone marrow with a myeloproliferative phenotype in a transition state from proliferation to senescence cellular state: the transition period of lower proliferation and high DDR activity; time of tamoxifen treatment: from 7 to 8 months of tamoxifen treatment in vivo; tissue: bone marrow