Among them, angiogenic factors, such as VEGF-A and PDGF; cytokines, such as transforming growth factor-β1 (TGF- β1), insulin-like growth factor (IGF), IL-6, and IL-8; and chemokines, such as C-X-C Motif Chemokine Ligand (CXCL)1/2/5 and C-C motif chemokine ligand (CCL)-2, also named monocyte chemoattractant protein 1 (MCP-1), have been shown to play important roles in stimulating cancer progression [130]. Here, CCL2 is linked to cancer.