IL2 and neoplasm: Several cytokines, including IFN-α, IFN-γ, IL-2, IL-12, IL-15, and granulocyte-macrophage colony-stimulating factor (GM-CSF), exhibit antitumor properties in preclinical models.7 These cytokines slow tumor growth either by directly inhibiting proliferation and promoting apoptosis, or indirectly by mobilizing an antitumor immune response.