The interaction of anticancer therapies with tumor-associated macrophages

Macrophages are essential components of the inflammatory microenvironment of tumors. Conventional treatment modalities (chemotherapy and radiotherapy), targeted drugs, antiangiogenic agents, and immunotherapy, including checkpoint blockade, all profoundly influence or depend on the function of tumor-associated macrophages (TAMs). Chemotherapy and radiotherapy can have dual influences on TAMs in that a misdirected macrophage-orchestrated tissue repair response can result in chemoresistance, but in other circumstances, TAMs are essential for effective therapy. A better understanding of the interaction of anticancer therapies with innate immunity, and TAMs in particular, may pave the way to better patient selection and innovative combinations of conventional approaches with immunotherapy.