MX1 and melanoma: Thus, the combined low levels or lack of IFN-β and PKR refractory to stimulation, together with the separate expression of ISGs, notably OAS and MxA, could create an environment favorable to MV replication acting as pro-apoptotic and anti-proliferative signals, mediating the death of melanoma cells comparing with normal cells, although the cell death mechanism depended on the cell line tested.