FGF2 and acute lymphoblastic leukemia: In contrast, a substantially lower abundance of typical CXCL12hiSCFhi CAR cells in ALL-MSC spheroids with weaker expression of CXCL12 and SCF (Figure 1B), but increased production of IL-8, Flt3-L, GM-CSF, FGF-2, CXCL10, and CXCL11, was observed in the supernatants evaluated at 24 h (Figure 1C).