HGF and cancer: Cancer-associated fibroblasts (CAFs) are another TME component that plays significant roles in tumor growth, metastasis and cancer therapy resistance by secreting various growth factors like Hepatocyte growth factor (HGF) and Epidermal growth factor (EGF); cytokines such as stromal cell-derived factor 1 (SDF-1) and interleukin-6 (IL-6) [20, 21].