ABL1 and leukemia: To ensure equal engraftment of disease in both backgrounds, the blood and bone marrow was analyzed for GFP and found to be similar in both Fgf2 +/+ and -/- mice at time of death (Figure 7B and Figure 7—figure supplement 1), suggesting that nilotinib was more effective at attenuating disease progression of BCR-ABL leukemia cells in an Fgf2 -/- microenvironment.