IL4 and neoplasm: Monocytes, originated in bone marrow and spleen, are recruited to tumors by both malignant stromal or tumor cell-derived chemokines and growth factors, and can differentiate in two subsets of macrophages, the M1-type macrophages that are activated by interferon gamma (IFN-γ), and the M2-type macrophages that are induced by exposure to cytokines, such as interleukin 4 (IL-4), IL-10, TGF-β, Ggranulocyte-macrophage colony stimulating factor (GM-CSF), Aannexin A1, or tumor cell-surface molecules [73,74,75].