TAMs are recruited to mammary tumors through induction of a variety of cytokines and chemokines including C-C Motif Chemokine Ligand 2 (CCL2), CCL3, CCL5, Colony Stimulating Facotor-1 (CSF-1/M-CSF), and Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF or CSF2) [9,10,11,12,13]. Here, CCL2 is linked to breast cancer.