The researchers, based at the University of Wolverhampton, studied 24 breast cancers that had spread to the brain, along with samples from the original breast tumour, and found a handful of genes with faulty switches. Crucially, two of the genetic switches became faulty early on in the development of breast cancer, suggesting they may be an early warning signal for tumours that will spread to the brain. The scientists are now working to develop a blood test that might be able to detect these signals at an early stage, before the disease has spread. Up to 30 per cent of breast cancers will eventually spread to the brain, often many years after the first tumour was treated…