A pair of studies suggests that CRISPR-based gene editing could boost cancer risk, Stat News reports.
Researchers from the Karolinska Institute and elsewhere report in Nature Medicine that CRISPR-Cas9 gene editing induces p53-mediated DNA damage response or cell cycle arrest within immortalized human retinal pigment epithelial cells. This, they add, then leads to selection against cells with a working p53 pathway. Similarly, researchers from Novartis and elsewhere also report in Nature Medicine that p53 inhibits the CRISPR-Cas9 engineering in human pluripotent stem cells.
And p53 dysfunction, Reuters notes, can cause cancer. Stat News adds that p53 mutations are common in ovarian, colorectal, lung, and many other cancers.
"By picking cells that have successfully repaired the damaged gene we intended to fix, we might inadvertently also pick cells without functional p53", Karolinska's Emma Haapaniemi says in a statement. "If transplanted into a patient, as in gene therapy for inherited diseases, such cells could give rise to cancer, raising concerns for the safety of CRISPR-based gene therapies."
Stat News adds that while other researchers have noticed effects on p53, they have not observed an increase in cancer among treated lab mice.
MarketWatch reports the shares of CRISPR companies fell upon the news of the findings. Intellia Therapeutics tells MarketWatch that it has "observed no signs of this type of toxicity or cells transforming into cancer or tumors" in either its in vivo or ex vivo programs.