Dual role of macrophages in tumor growth and angiogenesis

Abstract: During the neoplastic progression, macrophages as well as dendritic and NK cells are attracted into the tumor site and initiate the im-mune response against transformed cells. They ac-tivate and present tumor antigens to T cells, which are then activated to kill tumor cells. However, tumor cells are often capable of escaping the im-mune machinery. As the immune surveillance is not sufficient anymore, tumor-associated macro-phages contribute to tumor progression. It is nota-ble that tumor-associated macrophages promote the proliferation of tumor cells directly by secret-ing growth factors. They also participate in tumor progression by acting on endothelial cells and thus promoting the neovascularization of the tumor. Tumor-associated macrophages are indeed key protagonists during angiogenesis and promote each step of the angiogenesis cascade. J. Leukoc. Biol