Protumor Activities of the Immune Response: Insights in the Mechanisms of Immunological Shift, Oncotraining, and Oncopromotion

Figure 1

Cancer immunosurveillance activity. Each immune cell fulfills unique and redundant functions to achieve tumor cell elimination. Among the anti-tumor activities found in the tumor microenvironment are cytotoxicity mediated by CD8⁺ T and NK cells, phagocytosis by M1 macrophages, cytolysis induced by mast cells, and humoral responses by B cells. Dendritic cells are primed by tumor antigens, which are then presented to T and B cells for adaptive responses. These activities are coordinated by a variety of molecules secreted by the immune and tumor cells directly to the tumor environment or to circulation where it serves to recruit additional immune populations to the tumor site (see text for details). Red dashed arrows represent direct anti-tumoral effects, blue dashed arrows indirect tumor cell elimination. Dotted arrows represent recruitment of other cell populations.