Once delivered to cells, the CRISPR-Cas9 gene-editing system (purple and pink) cuts DNA in specific places.Credit: Ruslanas Baranauskas/SPL The powerful gene-editing technique CRISPR–Cas9 might offer a way to make safer, more effective cancer-fighting immune cells engineered inside the human body, a mouse study has found. Cancer-fighting immune cells could soon be engineered inside our bodies The research, reported on 18 March in Nature1, adds new safety features to an emerging class of cancer treatments known as chimeric antigen receptor (CAR)-T-cell therapies, which are produced in the body. The development could lead to treatments that are cheaper to make and easier to administer than are those currently used against some blood cancers. At present, CAR-T therapies are made from a person’s own T cells — a type of immune cell — which are isolated, engineered to express a synthetic protein known as a CAR and then reinjected into the body.…