Tumor‐associated macrophages: An important player in breast cancer progression

Breast cancer is the most common form of malignant tumor in females, accounting for the second highest mortality among cancer patients. In the breast tumor microenvironment, tumor‐associated macrophages (TAMs) are the most abundant immune cells, which regulate the progression of breast cancer. During breast cancer tumorigenesis and progression, TAMs support breast tumor growth by promoting angiogenesis and cancer cell metastasis, inducing cancer stemness, regulating energy metabolism, and supporting immune system suppression. TAMs exhibit a high degree of cellular plasticity. Repolarizing tumor‐related macrophages into M1 macrophages can promote tumor regression. This study reviews the role and mechanism of action of TAMs in the development of breast cancer and establishes TAMs as effective targets for breast cancer treatment. TAMs support the progression of breast cancer by promoting tumor cell invasion and metastasis, angiogenesis, cancer stemness, regulating energy metabolism, and modulating T cell activity.