Analysing and altering people’s genes is showing good promise as a way of treating or preventing cancer, although it is still early days.
Gene therapy is where you physically insert genes into someone’s cells. In the case of cancer, you are looking to replace mutated genes with working ones. It is a very complicated area of research, and progress up to the point where it is a regular form of treatment will be long and slow. However, it has shown promise in animal studies, and places like the Institute of Cancer Research, where I work, are researching it, and finding new ways of doing it, every day!