Abstract
The tumor microenvironment (TME) is a complex system composed mainly of tumor cells, mesenchymal cells and immune cells. Macrophages, also known as tumor‑associated macrophages (TAMs), among innate immune cells, are some of the most abundant components of the TME. They may influence tumor growth and metastasis through interactions with other cell populations in the TME and have been associated with poor prognosis in a variety of tumors. Therefore, a better understanding of the role of TAMs in the TME may provide new insight into tumor therapy. In the present review, the origin and classification of TAMs in the TME were outlined and their polarization and dual effects on tumor cells, as well as emerging strategies for cancer therapies targeting TAMs, were discussed.