Figure S1. FGFR1 is the most highly expressed FGFR in MOLM 14 and siRNA knock down of FGFR mRNA. Figure S2. FGF2 protection from FLT3 inhibitors is dependent upon FGFR expression. Figure S3. Matrix of AC220 and PD173074. Figure S4. STAT5 and ERK are downstream targets of FLT3. Figure S5. Resistant long-term cultures have very similar phosphorylated proteins to naïve MOLM14 cells. Figure S6. Identification of FLT3 point mutations by Sanger sequencing. Figure S7. Removing FL or FGF2 from resistant cultures results in partial reactivation of FLT3 either through point mutation or non-mutational activation. Figure S8. FGF2 is localized to bone marrow stromal cells and not in hematopoietic cells. Figure S9. FGFR1 and FLT3 do not interact directly. Figure S10. FGF2- and FL-mediated resistance has restoration of pSYK.