The present invention provides a method for the treatment of “interferon resistant” tumors (i.e., tumors resistant to treatment with exogenously-administered interferon polypeptide) through the use of a non-replicating agent which induces human cells to express interferon species. In particular it is noted that inducing interferon expression in the patient's body possesses properties not associated with exogenously-produced intravenously-administered interferon proteins. The present invention further provides compositions useful in the treatment of cancer resistant to treatment with exogenous interferon polypeptide, by using a non-replicating agent which induces human cells to express interferon species, e.g., an antigenic, replication-deficient virus optionally carrying an interferon transgene.