A Chinese group has become the first to inject a person with cells that contain genes edited using the revolutionary CRISPR–Cas9 technique. On 28 October, a team led by oncologist Lu You at Sichuan University in Chengdu delivered the modified cells into a patient with aggressive lung cancer as part of a clinical trial at the West China Hospital, also in Chengdu. Earlier clinical trials using cells edited with a different technique have shown promise at treating disease. The emergence of CRISPR, which is simpler and more efficient than other techniques, will probably accelerate the race to get gene-edited cells into the clinic, says Carl June, who specializes in immunotherapy at the University of Pennsylvania in Philadelphia and led one of the earlier trials.