Figure 3C shows findings from a mouse with T-ALL (mouse 1890). The CBC from this mouse revealed a hemoglobin of 10.6 g/dL, an elevated MCV of 65 fL, an elevated WBC of 36,500/μL, and a normal platelet count at 857,000/μL. The normal thymic architecture was effaced and replaced by sheets of lymphoblasts. IHC demonstrated cytoplasmic CD3 staining in the thymus, and the liver showed perivascular invasion of CD3+ cells. Of note, despite the fact that IHC was strongly positive for CD3, FACS analysis demonstrated that the cells were CD3-CD4+, and negative for Mac-1 and Gr-1. The gene discussed is CD4; the disease is acute lymphoblastic leukemia.