http://www.digitaljournal.com/science/developing-gene-therapy-to-lower-cancer-risks/article/424573

Developing gene therapy to lower cancer risks

Posted Jan 27, 2015 by Tim Sandle
Gene therapy is the primary method for treating rare, genetic diseases. However, many treatments carry the risk of cancer. A new study has attempted to lower this risk.
A laboratory technician works on blood samples of people living with HIV on September 13  2013
A laboratory technician works on blood samples of people living with HIV on September 13, 2013
Sia Kambou, AFP/File
In a mouse model of a rare disease, scientists have worked out how to reduce the elevated cancer risk tied to a gene therapy treatment. Researchers found that when treated with a gene therapy, mice designed to suffer from methylmalonic academia (a type of metabolism deficiency) responded well.
However, although the mice’s metabolic problems, and their related untoward effects, are reduced, the animals end up with an increased risk for liver cancer. Upon further exploration, researchers found that the gene therapy delivery vector’s insertion in the mouse DNA appeared to be responsible.
Gene therapy was first developed in 1972. At the time the authors urged caution before commencing gene therapy studies in humans. The first FDA-approved gene therapy experiment in the U.S. occurred in 1990.
In the second round of experiments, when researchers moved the insertion site to another part of the genome, the mice no longer developed cancer at the higher rates.
The implications of the research are that some forms of gene therapy can be cancer causing and that the site where the therapy is targeted may increase or lower the risk. Although the mouse study results do not directly transfer to people, the study’s outcomes give pause for thought and should trigger further inquiries.
The findings have been published in the Journal of Clinical Investigation.