Since recombinant IFNα is used for the treatment of some malignancies, several groups have incorporated type I IFN (IFNα2, IFNβ) or type II IFN (IFNγ) expression cassettes into Ad vectors to provide local expression at tumor sites and to reduce the systemic toxicity associated with infusion of recombinant IFNs. This evidence concerns the gene IFNB1 and neoplasm.