Tumor-Associated Macrophage in Breast Tumor Microenvironment

Breast cancer (BC) is the most common cancer in women worldwide. It is one of the main causes of cancer-related mortality. The breast tumor microenvironment (Br-TME) has emerged as an important factor related to BC development and prognosis. Tumor-associated macrophages (TAMs) are the main effector cells in the Br-TME; they play key roles in regulating angiogenesis, immunosuppression, metastasis, and chemoresistance in BC patients. In this review, we introduce the macrophage niche in the Br-TME, particularly emphasizing the origin of TAMs. Next, we summarize the typical pathways and molecular mechanisms of the interactions between TAMs and various other components in the Br-TME. Finally, we provide an overview of drugs that target TAMs and discuss the prevailing technologies for drug delivery in the context of BC treatment. Identification of the dynamic variations in tumor-promoting TAMs will help reveal the key links that drive BC progression. This review provides a theoretical basis for upcoming clinical trials that may substantially benefit patients.