Antitumoral compositions can comprise as therapeutic agent one or several immunogenic polypeptides, of which at least one is modified so as to have a cell location different from its native location. Compositions can be based on a recombinant vector expressing such an immunogenic polypeptide. A recombinant vector comprising at least the sequences coding for an immunogenic polypeptide originating from a precocious and/or tardive region of a papillomavirus having a modified location and a viral particle comprising said vector is also described. Finally, therapeutic uses of such a composition, such a recombinant vector and such a viral particle are described.