Presence of MDA-7/IL-24 in the uninjected tumors, albeit at lower levels, suggests that MDA-7/IL-24 secreted by the injected tumors might have entered the circulation and localized at the distant tumor site, or more likely the secreted protein interacted with IL-20/IL-22 receptors on the distant tumor, inducing MDA-7/IL-24 production through a “paracrine/autocrine” effect [22] thereby mediating tumor reduction. This evidence concerns the gene IL20 and neoplasm.