To address the possible role of Gadd45b in modulating bcr-abl induced leukemia, myeloid progenitor enriched bone marrow cells were isolated from both wild type and Gadd45b-/- mice and transduced with either control MSCV-IRES-EGFP, also termed as MIGR1, retrovirus vector or MIG-BCR-ABL encoding vector (Figure 1 Figure 2A). Here, ABL1 is linked to leukemia.