RIGI and cancer: The results showed that TLR3, TRIF, RIG-I, MDA5, LGP2, and MAVS, which were reported to be expressed in the A549 cell line, were expressed in all these cells lines at both the mRNA and protein levels (Figures 1A,B,D), indicating that the TLR–TRIF and RLR–MAVS pathways are constitutively intact in all cancer cells.