Establishment of PDX of JMML. (A) Immunophenotype of patient BM MNCs (left column) and tissues from a representative recipient mouse xenografted from the same patient (the percentages listed represent the percent of cells within the gate described above each plot; hCD45, human CD45; mCD45.1, mouse CD45.1). (B) Splenomegaly in JMML PDX mice when compared with spleens from NSGS mice injected with saline. (C) Kaplan-Meier survival curve of recipient NSGS mice engrafted with BM MNCs (n = 6) or PB MNCs (n = 6) from JMML patients (n = 4). (D) H&E and immunohistochemistry for hCD45⁺ cells in patient BM and the BM, spleen, and liver of xenografted BM MNCs from the same patient (scale bars for low-power field: 200 μm, original magnification ×100; scale bars for high-power field: 50 μm, original magnification ×1600). (E) H&E of 1 illustrative patient with lung hemorrhage at autopsy and the corresponding JMML PDX and saline-injected mouse for control (scale bars for low-power field: 200 μm, original magnification ×100; scale bars for high-power field: 50 μm, original magnification ×1600). (F) VAF of genomic DNA from BM MNCs from JMML patients (x-axis) and corresponding purified hCD45⁺ cells from engrafted NSGS mice at end stage (y-axis).