IL-7R plays a key role in LIC function and progression of human B-ALL. (A) Human primary B-ALL blasts were transduced with lentiviral vectors encoding shIL7R or a scrambled sequence (shsc), together with GFP, and cells were then injected into NSG immunodeficient mice. Mice were euthanized and analyzed for leukemic content when they presented advanced symptoms of disease. Transduction efficiency of transplanted B-ALL8 (from B-ALL patient 8) (A) and B-ALL9 (from B-ALL patient 9) (C) cells. Numbers indicate percentages of GFP⁺ transduced cells. Percentages of transduced (GFP⁺) B-ALL8 (B) and B-ALL9 (D) cells engrafting the indicated organs of host mice 10 to 11 weeks posttransplant. Mean (± SEM) percentages are shown (n = 4). **P < .01.