Professor Ian MacKenzie, a researcher in stem cell biology from the Queen Mary School of Medicine and Dentistry in London, said that it was still likely that stem cells played a significant role in the development of cancer.

BBC: NEWS | Health | Skin cell find offers cancer clue

Next year, Professor John Oxford, an expert in virology from Queen Mary's School of Medicine and Dentistry, in London, will lock volunteers in a hotel for a week, deliberately infect some with the flu virus, and wait to see what happens.

BBC: Colds and flu remain mysterious