MAPK3 and hepatocellular carcinoma: We modulated PKR expression in the HCV-replicating cell lines JFH-1 and H77 (generated by Huh7.5.1 cell transfection) using siRNA and a PKR expression plasmid, and we showed that PKR upregulates c-Fos and c-Jun activities through activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal protein kinase (JNK1), respectively, subsequently increasing HCC cell proliferation16.