A fraction of Asxl1^Y588XTg mice developed myeloid leukemia. (A) The gross appearance of spleen and liver of a WT mouse and a representative Asxl1^Y588XTg mouse with leukemia. (B) Photographs of a sarcoma from a leukemic Asxl1^Y588XTg mouse (left), histological (middle), and flow cytometric (right) analyses showed the predominant granulocytic/monocytic (Gr-1⁺/Mac1⁺) cells in the sarcoma. Bar represents 100 µm. (C) May-Giemsa–stained PB smears, BM, and spleen cell cytospins prepared from representative WT (top) and Asxl1^Y588XTg mice (bottom). Red arrow, blast cells. Bars represent 10 µm. (D,E) H&E-stained sections of femurs (D), H&E- and MPO-stained spleens (E, left), and H&E-stained livers (E, right) from representative WT (top) and Asxl1^Y588XTg mice (bottom). Bars represent 1 mm, 10 µm, 100 μm. (F) Flow cytometric analysis of cKit⁺/Mac1⁺ or Gr-1⁺/Mac1⁺ cells in the BM and spleen cells of representative recipient mice transplanted with spleen cells from a leukemic Asxl1^Y588XTg mice. Cells were gated on CD45.2⁺. (G) May-Grünwald-Giemsa–stained cytospins of the BM and spleen cells from representative recipient mice transplanted with spleen cells from a leukemic Asxl1^Y588XTg mice. Bars represent 10 µm.