Researchers at Stanford University have designed a new technique that may soon make this a reality. Tumours are called 'solid' or 'liquid' based on where in the body they grow. More than 80 percent of all cancers are caused by solid tumours that grow as a mass of cells in particular organ, tissue or gland. The new technique called CAPP-Seq (cancer personalised profiling by deep sequencing) is sensitive enough to detect just one molecule of tumour DNA in a sea of 10,000 healthy DNA molecules in the blood.