IFNAR1 and cancer: Many oncolytic viruses display a particular sensitivity towards innate antiviral immunity42 and utilise defects in these antiviral mechanisms to target cancer cells.8,43,44 Opposed to various human cancer models, which have been reported to commonly exhibit a reduced antiviral protection,31,45,46 most mouse tumour cell lines are sensitive to antiviral response mediators, such as type I IFNs.14,17,33 We therefore generated an IFNAR1 knockout mouse tumour cell line with disrupted IFN type 1 response.