M1 and M2 macrophages represent two extremes of the macrophage activation spectrum. While M1 macrophages are pro-inflammatory and anti-tumor, M2 macrophages are anti-inflammatory and often pro-tumor. M2 macrophages promote tumor growth and metastasis by secreting immunosuppressive cytokines like IL-10 and transforming growth factor-beta (TGF-β), as well as factors that promote angiogenesis and tissue remodeling.
