Abstract: A novel animal model for the treatment of skin tumors is described. In particular, the invention provides transgenic non-human animals comprising a recombinant nucleic acid molecule containing a nucleic acid sequence encoding at least one of the gene products of the early genes of a virus of the Human Papilloma Virus Group B1, in which the animal displays one or more clinical symptoms of a tumor. The transgenic animals can be used to screen anti-tumor agents and to identify the tumorigenic potential of compounds.