Further optimization assays showed that a cocktail of IL-7, IL-6, IGF-1, and FLT3L (FI76) and a combination of IL-7, IL-6, and IGF-1 (I76) were better than other tested combinations at expanding primary B-ALL cells from three patients (Figure 1E, 1F and Supplementary Figure 3). This evidence concerns the gene FLT3LG and acute lymphoblastic leukemia.