[Basic principles of gene therapy].

The rapid development of recombinant DNA technology and our enhanced understanding of the genetic basis of human disease has facilitated the development of new molecular therapeutic modalities, termed gene therapy. Gene therapy involves the transfer of functional genes into somatic cells and their expression in target tissues in order to replace absent genes, correct defective genes, or induce antitumoral activity in the tumor-bearing host. Currently, an increasing number of gene therapy strategies are being investigated in experimental and clinical trials. Despite substantial progress, a number of technical and logistical hurdles must still be overcome before gene therapy can be safety and effectively applied in the human patient. Since gene therapy involves complex cell processing and can be time consuming and costly, simplifications or even alternative approaches will be necessary in order to establish this therapy as suitable for clinical use. This report reviews various gene therapy strategies and gene delivery techniques currently under clinical or experimental investigation. Special emphasis is given to cytokine gene therapy using gene-modified tumor vaccines for cancer treatment.