Parallels between the anti-Viral State and the Irradiated State.

Improved understanding of host anti-viral defense and anti-tumor immunity have elucidated molecular pathways important to both processes. During viral infection, RNA or DNA in the host cell serve as danger signals that initiate anti-viral responses. Recent studies have elucidated similarities in signaling pathways activated by viruses and induced by tumor DNA released into the cytoplasm of irradiated tumor cells. The host defense to viral infection and the sterile inflammation provoked by radiotherapy both induce a type I interferon response that is necessary for pathogen control and immune-mediated tumor control, respectively. These findings have led to the hypothesis that radiotherapy employs a form of viral mimicry.