Two studies published in Nature Medicine June 11 contribute to a small body of literature suggesting cells edited with CRISPR-Cas9 may cause cancer.
Here are five things to know about the studies and their implications:
1. CRISPR, which stands for Clustered Regularly Interspaced Short Palindromic Repeats, is a gene-editing technology that enables scientists to modify an organism's DNA. Many scientists consider the CRISPR-Cas9 system — which creates modified RNA segments to exploit select enzymes — to be one of the most precise and least expensive gene-editing techniques in use.
2. The link to cancer comes down to a gene called p53, which suppresses tumors in cells, among other functions — and dysfunction in these genes can cause cancer. P53 mutations are associated with almost half of ovarian cancers, 43 percent of colorectal cancers and one-quarter of breast cancers, according to STAT.
3. In one study, researchers from the Novartis Research Institute in Boston tested CRISPR-Cas9 on human pluripotent stem cells. They found CRISPR-Cas9 activates the p53 gene, which attempts to mend or destroy cells with damaged DNA. As a result, only cells with dysfunction p53 survive the editing process.
4. The second study, published by researchers from Cambridge University in England and the Karolinska Institutet in Sweden, found similar results after using CRISPR-Cas9 on human retinal cells.
"Although we don't yet understand the mechanisms … we believe that researchers need to be aware of the potential risks when developing new treatments," Jussi Taipale, PhD, a biochemistry researcher and leader of the study said in a statement to Reuters. "This is why we decided to publish our findings as soon as we discovered that cells edited with CRISPR-Cas9 can go on to become cancerous."
5. Dr. Taipale emphasized he did not want to sound "alarmist" in his statement to Reuters, and noted his team was not arguing CRISPR-Cas9 was dangerous.