CXCL12 and neoplasm: CAF is an abundant source of VEGFA and other pro-angiogenetic factors such as platelet-derived growth factor C (PDGFC), fibroblast growth factor 2 (FGF-2), and C-X-C motif chemokine 12 (CXCL12/SDF-1), which directly or indirectly regulates tumor neovascularization [2,6,68].