TNF and neoplasm: In summary, incorporation of immunomodulatory cytokines IFN-α2, IFN-γ, TNF-α and IL-2 into treatment regimen can alter the tumor microenvironment in favor of T-cell function, whereas in situ injections of GM-CSF can induce and sustain highly immunosuppressive immune cell populations within the tumor, thus leading to poor tumor growth control.