Strategies of Gene Transfer and Silencing, and Technical Considerations

Cancer gene therapy is a relatively new modality that might ultimately revolutionize oncology. The basic principle is to alter the tumor genetically to enhance more traditional chemo- and radiation therapy schema. The last decade has seen tremendous progress and development of new technologies in the areas of vector delivery, tumor targeting, and numerous clever ways to increase tumor killing, including early attempts to modulate tumor gene expression by RNA interference. In recent years, attempts to image affected cells have also been part of these efforts. Many studies have proceeded to the preclinical stage and a fair number to early clinical testing with some showing encouraging results. However, real impact on patient survival remains to be seen. One major problem still to be overcome is the quantitative delivery of the vector into the tumor mass. The next decade is expected to resolve many of these technical issues and improve the treatment of patients. This chapter will discuss new technologies and provide a brief overview of the field.