BASICS OF CANCER GENE-THERAPY

Gene therapy is a rapidly evolving concept for the therapy of differen t forms of cancer: A number of phase-I clinical trials have recently b een initiated world wide. This review discusses the technical concepts underlying the protocols currently coming into clinics. Two tools ess entially constitute such concepts, the vector for efficient transfer a nd expression of the transgene in the cancer cell, and the therapeutic gene. The most advanced vectors ready for clinical use are the retrov irus- and adenovirus-derived vectors. The application of a broad spect rum of therapeutic genes can be classified into gene replacement of re place e.g. mutated tumor suppressor genes, gene addition to increase i mmunogenicity by cytokine genes or introduce prodrug genes for suicide induction and, thirdly, targeted affection of gene expression by anti sense oligonucleotides or expression of ribozymes e.g. directed agains t oncogene sequences. Cancer gene therapy holds great promise to becom e an important addition to the multimodality in the therapy of some fo rms of cancer.