Researchers have reported the first case of cancer caused by a virus widely used to deliver genes, but they say the risk is low.

A 13-month-old boy who received gene therapy for Hurler syndrome (MPS I) developed a brain tumor years later. This is the first known case where in vivo gene therapy has been linked to cancer. Tests showed that the virus used (AAV) inserted part of its DNA into the boy’s brain cell genome, activating the PLAG1 gene, which can cause cancer.

However, researchers emphasize that this is a rare case, and AAV has been safely administered to thousands of people so far. The incident highlights the importance of carefully weighing the risks and benefits of gene therapy and conducting long-term monitoring of recipients. Experts suggest considering the use of weaker promoters and extended follow-up to improve safety.

https://www.science.org/content/article/boy-s-brain-tumor-tied-gene-therapy