‘What is a tumour driver?’ This has been, and still is, the challenge of cancer research. Once we have the driver, the other challenge is can we make a drug against this driver? It’s not always easy. Some proteins – proteins are the drivers – have enzymatic activity; in this case, we go to an organic chemist and they recommend a chemical that will inhibit the protein growth. Some drivers, however, don’t have enzymatic activity, and it’s very difficult to find a drug for this type of driver.