However, little to no signal could be detected at later time points in parental LLC1, whereas the bioluminescence signal in VSV-GP-Luc treated LLC1-IFNAR1−/− tumours increased over several days before starting to decline after 5 days (Fig. 4a, b) indicating active viral replication in interferon insensitive tumours (∆radiance IFNAR1−/− vs wt LLC1 greater than 2 logs). Here, IFNAR1 is linked to neoplasm.