Kaplan-Meier survival analysis and histopathology. (A) Mice receiving transplants of bone marrow transduced with FLT3WT, FLT3-ITD, or FLT3-ITD–Y589/591F. The percentage of surviving mice (y-axis) is plotted with respect to time in days (x-axis). The number of mice per group is indicated. (B) Bone marrow from a mouse that received FLT3-ITD–transduced bone marrow ([i] magnification, ×100; [ii] magnification, ×600) shows hypercellularity and myeloid hyperplasia. Bone marrow from a mouse that received N51-Y589/591F–transduced bone marrow ([iii] magnification, ×100; [iv] magnification, ×600) appears normal with open sinuses and fat spaces and a normal myeloid-erythroid ratio. Spleen sections from a mouse that received FLT3-ITD–transduced bone marrow ([v] magnification, ×100; [vi] magnification, ×600) demonstrate myeloid infiltration and effacement of splenic architecture by expansion of red pulp. Spleen sections from a mouse that received N51-Y589/591F–transduced bone marrow ([vii] magnification, ×100; [viii] magnification, ×600) show preserved areas of white pulp and no red pulp expansion. Hematoxylin and eosin was used in each panel.