IFIH1 and cancer: MDA5 (melanoma differentiation-associated gene 5), an intracellular sensor of viral RNA that triggers the innate immune response and RIG-I (Retinoic Acid-Inducible Gene I Protein), is involved in viral double-stranded RNA recognition, regulation of the antiviral innate immune response, and acted in PI3K-Akt-independent pathways, thus suggesting a new signal transduction pathway, leading to MDA5- and RIG-I-mediated mitochondrial apoptosis in cancer cells [108].