Abstract: The present invention provides a method of destroying selected tumor cells comprising administering to a warm-blooded animal a vector construct which directs the expression of at least one immunogenic, non-tumorigenic form of an altered cellular component normally associated with the selected tumor cells. Also provided are vector constructs which direct the expression of altered cellular components. Representative altered cellular components include ras.sup.*, p53.sup.*, Rb.sup.*, alter protein encoded by the Wilms' tumor gene, ubiquitin.sup.*, mucin.sup.*, DCC, APC, MCC, neu, an altered receptor, and bcr/abl. Also provided are recombinant viruses carrying a vector construct, target cells infected with the recombinant virus, and pharmaceutical compositions comprising the recombinant virus and a pharmaceutically acceptable carrier or diluent.