Gene therapy for cancer: from the laboratory to the patient.

Gene therapy is a new form of therapeutic intervention with applications in many areas of medical treatment. There are still many technical difficulties to be overcome, but recent advances in the molecular and cellular biology of gene transfer have made it likely that gene therapy will soon start to play an increasing role in clinical practice and particularly in the treatment of cancer. The first clinical gene transfer in an approved protocol took place exactly 10 years ago, and it was for the transfer of gene-marked immune cells into patients with advanced cancer. Now there are 218 active clinical protocols in the United States, and they have involved over 2000 patients worldwide. Among the conditions and diseases for which gene transfer is being tried as treatment, cancer comes first with 130 clinical trials. Fundamental research in the mechanisms of cancer and the development of molecular biology tools are crucial for the success of the treatments in the future. The identification of tumor rejection antigens from a variety of cancers and the immune response that is defective in cancer patients are important topics for future studies. The evaluation of gene therapy combinations involving use of tumor suppressor genes and constructs that inactivate oncogenes is also another important area for future research. The future improvement of present viruses as well as the use of new viral vectors will likely expand the applicability and efficacy of gene therapy. During the next decade technological developments, particularly in the areas of gene delivery and cell transplantation, will be critical for the successful clinical practice of gene therapy.