CXCL12 and neoplasm: In addition to VEGF, other cytokines derived from MDSCs promote tumor angiogenesis, such as MMP9 (141), TGF-β (142), fibroblast growth factor-2 (FGF-2) (143), IL-1β (143), bombina variegata peptide 8 (Bv8) (144), stromal cell-derived factor-1 (SDF-1) (145) and so on.