Gene editing involves altering or disabling existing genes, which used to be extremely difficult. It took many years to develop the gene-editing tool that saved Layla, but thanks to a revolutionary method known as CRISPR, this can now be done in just weeks.
In fact, CRISPR works so well that the first human trial involving the method has already begun. In China, it is being used to disable a gene called PD-1 in immune cells taken from individuals with cancer. The edited cells are then injected back into each person’s body. PD-1 codes for an “off switch” on the surface of immune cells, and many cancers evolve the ability to thwart immune attacks by flipping the PD-1 switch to “off”. On the edited immune cells there is no switch for cancer cells to flip.