AML blasts in BM and peripheral tissues. (A) Differential counts were performed on Wright-Giemsa–stained cytospins of FACS-purified Bex⁺Vex⁺ myeloid scatter-gated cells isolated from BM of control Bex;Vex (n = 5), moribund RE;c-Kit^D814V (n = 4), and moribund RE;c-Kit^{T417IΔ418-419} (n = 6) mice. Data are mean ± SD (percentages) of the indicated myeloid cell subsets determined by typing 350 to 500 cells per sample. nd indicates not detected. (B) Representative H&E-stained tissue sections of BM, spleen, liver, and lung from Bex;Vex control, leukemic RE;c-Kit^D814V, and leukemic RE;c-Kit^{T417IΔ418-419} mice. Data are representative of a minimum of 5 moribund RE;c-Kit^D814V and RE;c-Kit^{T417IΔ418-419} mice. Original magnifications in the left and right columns of Bex;Vex, RE;c-Kit^D814V, and RE;c-Kit^{T417IΔ418-419} images were ×100 and ×630, respectively. (C) Splenomegaly was observed in all moribund RE;c-Kit^D814V and RE;c-Kit^{T417IΔ418-419} mice. Spleen weights (grams) are presented as mean ± SD for Bex;Vex controls (n = 10), RE;c-Kit^D814V (n = 8), and RE;c-Kit^{T417IΔ418-419} (n = 12). *P < .01, compared with Bex;Vex controls (unpaired t test).