Tumour-associated macrophages as treatment targets in oncology

Tumour-associated macrophages (TAMs) are a key component of the cancer microenvironment, and influence tumour growth and progressionTAMs can have a dual supportive and inhibitory influence on cancer, depending on the disease stage, the tissue involved, and the host microbiotaTAMs can limit the antitumour activity of conventional chemotherapy and radiotherapy by orchestrating a tumour-promoting repair response to tissue damage, and by providing a protective niche for cancer stem cellsConversely, TAMs contribute to the antitumour activity of selected chemotherapeutic agents, such as doxorubicin (under certain conditions), and of monoclonal antibody therapies via antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis (ADCP)Of note, macrophage depletion has a key role in the antitumour activity of the clinically approved anticancer agent trabectedinTherapeutic strategies targeting macrophages as tumour-promoting factors, and/or aimed at macrophage activation and re-education are undergoing clinical assessment; such strategies have the potential to complement cytoreductive, antiangiogenic, and immune-checkpoint-inhibitor treatments