Cytokines in lung cancer

Abstract

Cytokines are hormonE-like proteins and peptides involved in the signalling between cells during immune response. They are produced mainly by lymphocytes (lymphokines) and mononuclear phagocytes (monokines). They are involved in both cell-mediated and humoral immunity. Cytokines fall into a number of categories: interferons (IFNs), interleukins (ILs) and growth factors. It has been indicated in cancer immunology the following cytokines are particularly important: IFNs, TNF-alpha, IL-1, IL-2, IL-4, IL-6, IL-7, IL-9, IL-10, IL-12. Interferons (IFN-gamma in particular) in cooperation with TNF-alpha and IL-1 inhibit proliferation of tumor cells and by their synergic activity with IL-2 induce cytotoxicity of NK-cells. They activate mononuclear phagocytes and by B lymphocyte stimulation augment lysis of cancer cells. TNF-alpha has mainly cytotoxic activity, leading to hemorrhagic necrosis of tumors. It is also an endogenic pyrogen which is together with IL-1 responsible for pyretic status in neoplastic disease. IL-1 stimulates necrotizing activity of TNF-alpha and augments cachexia by anabolism of lipid induction. IL-2, IL-6 and IL-12 induce NK and LAK-cell cytotoxicity. IL-12 inhibits metastasis formation. IL-10, by inhibiting synthesis of cytokines may lead to tumor development.