HGF and neoplasm: CAFs may support the malignant progression of tumors by promoting tumor growth, survival, invasion, and metastasis through the secretion of stroma-modulating growth factors such as TGF-β1, hepatocyte growth factor (HGF) [27], vascular endothelial growth factor (VEGF) [28], and stromal cell derived factor-1 (SDF-1) [20, 29].