Leukemia is transplantable and rapidly progressing in secondary recipients. (A) Schematic representation of the secondary transplant, in which primary Csnk–/+p53 leukemic bone marrow was transplanted into 5 sublethally irradiated WT recipients and euthanized after 28 days. Secondary recipients of bone marrow cells received sublethal irradiation (6 Gy) and received transplantation with 2.5 × 106 bone marrow cells from leukemic mouse (00-1) each. All mice developed disease rapidly and were moribund within 4 weeks after transplant. (B) Peripheral blood counts at time of euthanasia show leukocytosis and elevated hemoglobin (HGB) levels in 3 of 5 mice. Platelet counts were normal. Reference levels are highlighted by purple rectangles. (C) Peripheral blood smears with MGG staining show infiltration with large basophil blasts. Scale bar, 100 μm. (D) Bone marrow cytospins with MGG staining show basophil blasts; scale bar, 50 μm. (E) Histograms demonstrating the surface marker expression profile of leukemic blasts analyzed by flow cytometry gated on alive/lineage negative cells. Blue curve represents healthy control bone marrow, and red curve represents bone marrow of leukemic secondary recipients. (F) Hematoxylin and eosin (HE) stainings of femur (scale bar, 100 μm) and spleen (scale bar, 200 μm) sections. (G) Total number of single nucleotide variants and small insertions and deletions identified by whole exome sequencing of immortalized blasts (IMMs), primary transplants (leukemic vs nonleukemic), and secondary transplants (transformed vs nontransformed) after indicated filtering steps.
