Proliferative activity and in vitro replication of HSV1716 in human metastatic brain tumours.

Background: The neurotropic herpes simplex virus mutant HSV1716 lacks the gene encoding the virulence factor ICP34.5 and cannot replicate in non-dividing cells where proliferating cell nuclear antigen (PCNA) is not actively engaged in cellular DNA synthesis. In the brain, tumoral expression of PCNA therefore confers on it oncolytic specificity and may determine its efficacy.