CAR-macrophage: A new immunotherapy candidate against solid tumors

Chimeric antigen receptor (CAR)-T cell therapy has been shown to be an effective treatment for hematological tumors, but the treatment of solid tumors still lacks effectiveness. In the tumor microenvironment, macrophages are the innate immune cells with the highest infiltration rate. Tumor-associated macrophages (TAMs) stimulate angiogenesis, increase tumor invasion, and mediate immunosuppression. Because macrophages can infiltrate solid tumor tissue and interact with almost all cellular components in the tumor microenvironment (including tumor cells, immune cells such as T-cells, NK cells, DCs, and other resident non-immune cells), researchers are trying to use macrophages modified with CAR (CAR-M) against solid tumors. This review describes recent reports of CAR-M-based tumor treatments and summarizes their shortcomings and future applications.