CXCL12 and cancer: In cancer, however, fibroblasts can become cancer-associated fibroblasts (CAFs), which are characterized by rapid proliferation and production of tumor-promoting factors (e.g., VEGF (vascular endothelial growth factor), SDF1 (stroma-derived factor 1), HGF (hepatocyte growth factor) or CXCLs (Chemokine [C-X-C Motif] Ligands)) that enhance tumor growth and progression [44].