Gene therapy for the treatment of cancer

The delineation of the molecular basis of neoplasia provides the possibilit y of specific intervention by gene therapy through the introduction of gene tic material for therapeutic purposes. In this regard, several gene therapy approaches have been developed for the treatment of cancer: mutation compe nsation, genetic immunopotentiation, molecular chemotherapy, inhibition of angiogenesis, replicative vector oncolysis, and chemosensitization or radio sensitization. Clinical trials have been initiated to evaluate safety, toxi city, and efficacy of each of these approaches, based on promising preclini cal results. Various limitations that have been identified include lack of in vivo selective tumor delivery of vectors, minimal expression of therapeu tic genes, immune response against vectors, and normal tissue toxicity. Com bined modality therapy with gene therapy and chemotherapy or radiation ther apy has shown promising results. It is expected that as new therapeutic tar gets and approaches are identified, combined with advances in vector design , that gene therapy will play an increasing role in clinical cancer treatme nt.