A common virus which causes stomach upsets is giving hope to cancer patients - by boosting their immune system and blasting away tumours. Almost 80 patients with advanced forms of liver cancer, head and neck tumours and breast cancer are taking part in trials using a drug made from the reovirus. A number, who have struggled to benefit from chemotherapy, have seen astonishing results, with tumours shrinking and in one case disappearing altogether. Experts say it is too soon to say if Reolysin is the 'magic bullet' that will kill off cancer, but they believe it may offer a way...