TKT and hepatocellular carcinoma: Unlike the vital role of thymidine kinase (TK; an HSV-encoded gene product and a mediator enzyme that plays a critical role in HSV replication) in HSV pathogenesis, resveratrol at concentrations of 10 and 20 μM was found to boost the bystander action induced by the HSV-TK/ganciclovir gene therapy for hepatocellular carcinoma associated with herpesvirus infections by improving connexin-mediated gap junctional communication [58].