Macrophage Regulation of Tumor Responses to Anticancer Therapies

Tumor-associated macrophages (TAMs) promote key processes in tumor progression, like angiogenesis, immunosuppression, invasion, and metastasis. Increasing studies have also shown that TAMs can either enhance or antagonize the antitumor efficacy of cytotoxic chemotherapy, cancer-cell targeting antibodies, and immunotherapeutic agents—depending on the type of treatment and tumor model. TAMs also drive reparative mechanisms in tumors after radiotherapy or treatment with vascular-targeting agents. Here, we discuss the biological significance and clinical implications of these findings, with an emphasis on novel approaches that effectively target TAMs to increase the efficacy of such therapies.

► TAMs may either enhance or limit the efficacy of chemotherapy
► TAMs protect tumors from the effects of radiation and vascular-targeting agents
► TAMs enhance the activity of therapeutic antibodies via ADCC or ADCP
► Targeting or reprogramming TAMs may improve the efficacy of anticancer therapies