Free fatty acids (FFAs) [133], monocyte chemoattractant protein-1 (MCP-1) [134], CC-chemokine ligand 5(CCL5) [135], and insulin-like growth factor 1 (IGF-1) [136] secreted by CAAs can induce breast cancer cells to be more invasive or more proliferative. Here, CCL2 is linked to breast cancer.