Natural killer cells are our bodies’ first line of defense against harmful pathogens like bacteria and viruses. They can also detect and destroy abnormal cells such as tumour cells. Now researchers have equipped these immune cells with molecular guidance devices that enable them to home in on cancer cells and attack them. Laboratory studies of these engineered natural killer cells have been promising, with the cells performing as well as existing immunotherapies. Natural killer cell-based immunotherapies are currently being tested in clinical trials for brain and blood cancers. Read more in a story from Science.