The microenvironment in Crebbp^+/− mice does not induce leukemogenesis. Presented are 2 of 4 primary Crebbp^+/− recipients (top 2 horizontal rows) and 1 of 4 wild-type controls (bottom row). (A) PB smears (BX41 microscope; Olympus DP71 Digital Imaging System) at a magnification of 40×. (B) BM touch preparations at a magnification of 100×. (C) FACS profiles of donor-derived Gr-1loCD11b⁺ and Gr-1hiCD11b⁺ myeloid cells in the BM. (D) Frequencies of donor-derived, wild-type Gr-1hiCD11b⁺ granulocytes in the PB of wild-type (●) and Crebbp^+/− secondary recipients (○). The dashed red line represents the frequency of wild-type myeloid cells in the PB of the primary recipient from which BM was obtained for these secondary recipients.