Research progress and trends on M2 macrophages in breast cancer research: a bibliometric analysis

M2 macrophages play a crucial role in breast cancer progression through their immunomodulatory functions in the tumor microenvironment. This study aimed to conduct a bibliometric analysis of research trends on M2 macrophages in breast cancer. A literature search was conducted using the Web of Science Core Collection database. Bibliometric tools, including VOSviewer, CiteSpace, and the R package “bibliometrix”, were employed. A total of 675 articles were analyzed, with an annual growth rate of 28.75% and average citations per document of 38.25. China dominated publication productivity (395 articles, 58.5%), with Sun Yat-sen University as the leading institution (54 articles), and Takabe Kazuaki as the most productive author (12 total publications). Keyword co-occurrence analysis identified five major research clusters, focusing on molecular mechanisms and functional regulation of M2 macrophages, immunoregulatory roles within the tumor microenvironment, M2 macrophage–associated biomarkers and therapy resistance, macrophage activation and plasticity as therapeutic targets, and the clinical relevance of M2 macrophage phenotypes in prognosis and recurrence. Keyword burst analysis revealed a clear temporal shift around 2020, indicating a transition from mechanism-oriented studies toward translational and clinically oriented research, with increasing attention to tumor microenvironment interactions, therapy resistance, pathway-oriented strategies, and macrophage-targeted approaches. This bibliometric analysis outlines the major research hotspots and evolving trends in M2 macrophage–related breast cancer studies. Recent research has shifted from mechanism-oriented exploration toward translational and clinically relevant themes, with increasing emphasis on tumor microenvironment interactions, therapy resistance, macrophage plasticity, and pathway-oriented targeting strategies.