In contrast, mast cells inhibit tumor growth, by releasing IL-1, IL-2, IL-4, IL-6, IL-10 (low expression), monocyte chemotactic protein-3 and -4 (MCP-3 and -4), histamine through H2 receptors, interferon alpha  (IFNα), transforming growth factor (TGF)-β, tumor necrosis factor (TNF)-α, and leukotriene B4 (Ribatti and Crivellato 2009) (Fig. 1). Here, IL10 is linked to neoplasm.