Beside IL-17, vascular endothelial growth factor (VEGF) and granulocyte-macrophage colony-stimulating factor are predominately recognized as pro-tumor factors in the microenvironment, but it may not be reasonable to attribute an exclusive pro- or anti-tumor effect to any signal protein, cytokine, cell type or receptor-ligand interaction. The gene discussed is IL17A; the disease is neoplasm.