[Gene therapy and cancer].

Gene therapy by definition aims at modifying the genetic program of a cell towards a therapeutic or prophylactic goal. Several gene therapy strategies for cancer are currently under evaluation: 1) "suicide" gene therapy where an inactive prodrug is converted into a cytotoxic drug; 2) modification of the function of oncogenes and tumor suppressor genes; 3) modification of the host immune response towards the tumor; 4) disruption of the tumor neovascularisation; 5) lysis of tumor cells with replication-competent viruses. Recent results of phase I and II clinical studies have brought great hopes. However, the inefficiency of current gene vectors in infecting targeted cells and their inability to selectively access diseased cells distributed systemically are two major limitations that have to be overcome for further successful clinical applications.