Mpl is predominantly expressed in CD41⁺ Evi1 leukemia cells. (A) Mpl expression was measured by quantitative real-time polymerase chain reaction in CD41⁺ and CD41⁻ BM cells of Evi1 leukemia mice. BM-MNCs were harvested from 5 independent mice, and CD41⁺ and CD41⁻ cells were sorted. Expression levels relative to normal c-kit⁺ BM cells are presented. Error bars indicate SD (*P < .05, Student t test). (B-C) FACS analysis of CD41 and Mpl expression in BM- and SP-MNCs from Evi1 leukemia mice. (B) Cells were stained with PE-conjugated anti-CD41 and Alexa Fluor 647–labeled anti-mouse Mpl antibodies. Expression profiles were analyzed for GFP⁺ cells. (C) Mean fluorescence intensity (MFI) of Mpl was quantified in CD41⁺ and CD41⁻ cells. Error bars indicate SD (n = 8; ***P < .001, Student t test).