Researchers have developed cancer-killing 'sticky balls' that can destroy tumour cells in the blood and may prevent cancer spread. The most dangerous and deadly stage of a tumour is when it spreads around the body. Scientists at Cornell University in the US have designed nanoparticles that stay in the bloodstream and kill migrating cancer cells on contact the BBC reported. They said the impact was 'dramatic' but there was 'a lot more work to be done'. The team at Cornell attached a cancer-killing protein called Trail which has already been used in cancer trials and other sticky proteins to tiny spheres or nanoparticles.