ABSTRACT
Tumor brings great threat to human public health. In recent years, incidence rate and mortality of tumor were rapidly increased in the world. Anti-tumor therapies have undergone the development of cytotoxic therapy, targeted therapy, and immunotherapy. Among them, tumor immunotherapy is rapidly developed and becomes an important anti-tumor therapy in recent years, although it also brings some related side effects. Tumor microenvironment (TME) is composed of immune cells, vascular vessels, fibroblasts, the extracellular matrix, etc. TME significantly affects the efficacy of immunotherapy. Macrophages in the TME are named as tumor associated macrophages (TAMs). Recently, increasing studies have shown that TAMs play an important role in the regulation of tumor immunity, especially in tumor immune surveillance and immune escape. Currently, more and more anti-tumor immunotherapy strategies targeting TAMs are at the development stage. Based on the important role of TAMs in the TME and their potential as therapeutic targets in tumor immunotherapy, we first reviewed the subtypes and functions of TAMs, as well as the roles of TAMs in tumors. Furthermore, we summarized the research progress on anti-tumor strategies targeting TAMs and the current status of drug targeting TAMs. The current review will provide new ideas and novel insights for tumor immunotherapy.