gene therapy - the future of medicine?

Gene transfer to human patients may be ex vivo or in vivo.
Ex vivo gene therapy. Ex vivo gene transfer techniques usually involve the genetic alterations of cells (cell lines or human cells), mostly by use of viral vectors, prior to implanting these into the tissues of the living body. These methods have been frequently used in clinical trials because they are usually more efficient than in vivo methods. One disadvantage is that reimplantation of genetically engineered cells grown in culture may not result in long-term survival of a large portion of the cells unless they are protected by encapsulation before injection.In vivo gene delivery may be local (in situ) or systemic. In situ gene therapy means the introduction of genetic material directly into a localized area in the human body. The site of gene delivery may be irrelevant in systemic delivery with some form of targeting, provided the therapeutic molecule is released effectively and can reach its final site of action. In vivo gene delivery is likely to combine specific targeting systems with novel transcription switches.