['Sorafenib is the standard systemic therapy for unresectable or recurrent hepatocellular carcinoma (HCC) but adds minimal increase in survival. Therefore, there is a great need to develop novel therapies for advanced or recurrent HCC. One emerging field of cancer treatment involves oncolytic viruses that specifically infect, replicate within, and kill cancer cells. In this study, we examined the ability of GLV-1h68, a recombinant vaccinia virus derived from the vaccine strain that was used to eradicate smallpox, to kill sorafenib-resistant (SR) HCC cell lines.', 'Four SR HCC cell lines were generated by repeated passage in the presence of sorafenib. Median inhibitory concentration was determined for all cell lines. The infectivity, viral replication, and cytotoxicity of GLV-1h68 were assayed for both parental and SR HCC cells.', 'Infectivity increased in a time and concentration-dependent manner in all cell lines. All cell lines supported efficient replication of virus. No difference between the rates of cell death between the parental and SR cell lines was observed.'] Does oncolytic immunotherapy using recombinant vaccinia virus GLV-1h68 kill sorafenib-resistant hepatocellular carcinoma efficiently?