Editing Plasmid (section)

===Gene therapy===
{{main|Vectors in gene therapy}}
Plasmids may also be used for gene transfer as a potential treatment in [[gene therapy]] so that it may express the protein that is lacking in the cells.  Some forms of [[gene therapy]] require the insertion of therapeutic [[gene]]s at pre-selected [[chromosome|chromosomal]] target sites within the human [[genome]]. Plasmid vectors are one of many approaches that could be used for this purpose. [[Zinc finger nuclease]]s (ZFNs) offer a way to cause a site-specific [[double-strand break]] to the DNA genome and cause [[homologous recombination]]. Plasmids encoding ZFN could help deliver a therapeutic gene to a specific site so that [[cell damage]], cancer-causing mutations, or an [[immune response]] is avoided.<ref name= Kandavelou>{{cite book |vauthors=Kandavelou K, Chandrasegaran S |year=2008|chapter=Plasmids for Gene Therapy|title=Plasmids: Current Research and Future Trends|publisher=Caister Academic Press|isbn= 978-1-904455-35-6}}</ref>