CXCL12 and neoplasm: Once in close proximity to transformed cells in tumoral ducts, CAF favor tumor growth as a result of overexpression of hepatocyte growth factor (HGF), heparin-binding epidermal growth factor (HB-EGF) [87], TGFβ and stromal cell-derived factor (SDF)-1 (also known as CXCL12) [71].