CCR2 and breast neoplasm: Classical monocytes are believed to be a major source of TAMs, as they are robustly recruited to primary tumors and metastatic sites, while nonclassical monocytes display much lower levels of recruitment.2, 48, 51 Although CCR2‐deficient monocytes have impaired recruitment into murine breast tumors compared to wild‐type mice,90 CCR2‐deficient mice do not display reduced accumulation of TAMs in PyMT breast tumors,48 indicating that CCR2 signaling may not be required for TAM accumulation.