COMPOSITION FOR implementing an antitumoral or antiviral treatment in a mammal

The invention concerns a composition for implementing an antitumoral or antiviral treatment in a mammal comprising: (i) a nucleic acid sequence coding for all or part of polypeptide p53; (ii) at least a nucleic acid sequence coding for all or part of a polypeptide having at least a cytotoxic activity, said nucleic acid sequences being placed under the control of elements required for their expression in a host cell of said mammal.