To induce IRF signaling, human hepatoma HepG2 cells, which support viral genome replication, were transfected with one of three viral protein expression constructs — core, polymerase (Pol), or HBx —, a TLR3 expression construct , and a reporter construct expressing luciferase under control of the IFNβ promoter (Fig. 1A). The gene discussed is IFNB1; the disease is hepatocellular carcinoma.