CXCL12 and neoplasm: Among the TME cells, CAFs are the major cells that secrete growth factors, including hepatocyte growth factor (HGF), epidermal growth factor (EGF), stromal cell-derived Factor 1 (SDF-1), IL-6, exosomes containing miRNAs and others, to mediate tumor growth, monocyte recruitment, immunosuppression, and resistance to therapy 35.