CSF2 and neoplasm: However, the expression of cytokines, including IL-2, IFN-γ, tumor necrosis factor (TNF)-α, granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-4, and cytokine receptors such as IL-2R, IL-4R, IL-12R, and IL-15R, is up-regulated in CIK cells upon stimulation by tumor cells [16,24].