Advances in tumor immunotherapy targeting macrophages.

Introduction: In recent years, immunotherapy has shown significant therapeutic potential in patients with advanced tumors. However, only a small number of individuals benefit, mainly due to the tumor microenvironment (TME), which provides conditions for the development of tumors. Macrophages in TME, known as tumor-associated macrophages (TAM), are mainly divided into M1 anti-tumor and M2 pro-tumor phenotypes, which play a regulatory role in various stages of tumorigenesis, promote tumorigenesis and metastasis, and cause immunotherapy resistance.

Areas covered: This review focuses on research strategies and preclinical/clinical research progress in translating TAM into antitumor phenotype by referring to the PubMed database for five years. These include small molecule chemotherapy drug development, metabolic regulation, gene editing, physical stimulation, nanotechnology-mediated combination therapy strategies, and chimeric antigen receptor-based immunotherapy.

Expert opinion: It is necessary to explore the surface-specific receptors and cell signaling pathways of TAM further to improve the specificity and targeting of drugs and to strengthen research in the field of probes that can monitor changes in TAM in real time. In addition, the physical stimulation polarization strategy has the advantages of being noninvasive, economical, and stable and will have excellent clinical transformation value in the future.