Cbl mutants induce a myeloid leukemia or mast cell sarcoma. Histopathology of the bone marrow (BM), liver, and spleen from mice transplanted with Cbl mutant-transduced bone marrow cells. Spleen, liver, and bone marrow sections (hematoxylin and eosin [HE], Giemsa, NACE; original magnifications, 100×-1000×) from a representative leukemic mouse (Cbl-R420Q) and a mouse with mast cell sarcoma (Cbl-70Z), which received bone marrow cells transduced with Cbl-R420Q or Cbl-70Z, respectively. Normal organ architecture is visible in a control mouse. The leukemic mouse (Cbl-R420Q) reveals a massive infiltration of immature myeloid cells with its maximum in the spleen and consecutive destruction of the normal organ structure. There are also mast cells sporadically visible in between the immature cell infiltration (arrow in the spleen pictures and Giemsa staining). In contrast, mast cells in the mice with mast-cell sarcoma have characteristic cytology with uniform, closely packed cells with round nuclei and clear, abundant cytoplasm with granules and the typical features of mast cells with numerous granules in Giemsa staining and are highly positive in NACE staining. Slides were viewed with an Olympus BX51 microscope using Olympus Soft imaging system: Cell A and the following objective lenses: 10×/0.30 UPlanFL (1st column); 40×/0.75 UPlanFL (2nd column); 100×/1.35 oil iris PlanApo (3rd and 4th columns). Images were captured on an Olympus DP70 camera and manipulated with Adobe Photoshop DP70.