Crispr Therapeutics led gene-editing stocks lower after new studies published by Nature Medicine found that cells whose genomes are edited with the CRISPR-Cas9 technology have the potential to cause cancer, Stat News reports.

Editing cells' genomes with CRISPR-Cas9 might increase the risk that the altered cells, intended to treat disease, will trigger cancer, two studies published on Monday warn — a potential game-changer for the companies developing CRISPR-based therapies.

Crispr fell as much as 14%; Editas Medicine and Intellia Therapeutics dropped as much as 9.5%; Sangamo Therapeutics slipped as much as 4.3%

The findings come as Crispr is preparing to start its first clinical study in people in Europe in the second half of the year; the FDA has paused the company's plans to do a similar trial in the U.S.