C/EBPβ deficiency alters the BCR–ABL-dependent myeloproliferative status in vivo. Wright Giemsa staining (scale bar, 20 μm; original magnification, ×400) (a), 20 days post-transplantation, and flow cytometric analysis (b), 28 days post-transplantation, of peripheral blood from recipient mice transplanted with BCR–ABL-transduced WT cells or BCR–ABL-transduced C/EBPβ KO cells. Numbers in quadrants indicate the percentages within peripheral blood nucleated cells. (c) Peripheral white blood cell count of recipients after transplantation. Data are expressed as mean±s.d. (n = 4 each; *P<0.05). (d) Splenomegaly observed in recipients at day 19 after transplantation (scale bar, 10 mm). Spleen weights are presented as mean±s.d. (WT, n = 9; KO, n = 6; *P<0.01). (e) Survival of recipients transplanted with BCR–ABL-transduced WT cells or BCR–ABL-transduced C/EBPβ KO cells (WT, n=12; KO, n = 11; *P=0.0005).