Scientists are reporting a significant milestone for cancer research after charting 21 major mutations behind the vast majority of tumours. The disruptive changes to the genetic code, reported in Nature, accounted for 97% of the 30 most common cancers. Finding out what causes the mutations could lead to new treatments. Some causes, such as smoking are known, but more than half are still a mystery. Cancer Research UK said it was a fascinating and important study. A tumour starts when one of the building blocks of bodies, a cell, goes wrong. Over the course of a lifetime cells pick up...