By Matt McGrath
Health correspondent, BBC News
Scientists say they have found a mysterious link between cancer in humans and the lifespan of a tiny worm.
Cancer cells produce many proteins
In the journal Science, the Californian team says a protein that can prevent cancer in people plays a key role in making microscopic worms live longer.
Statistically, the longer you live, the greater your chances of getting cancer.
But even though scientists acknowledge the truth of this equation, they simply cannot understand why that should be the case.
Lack of protein?
One of the key elements in determining if a human cell turns cancerous is a so-called "checkpoint" protein.
This prevents cancer in people by stopping damaged cells from dividing.
Now scientists in California have found that when they removed this same protein from the tiny worm C. elegans, the worms lived up to 30% longer than normal.
The scientists deduced that a lack of this protein might mean that humans also live longer, but with an increased risk of getting cancer.
The researchers think the protein's dual function raises another important question: does the presence of this protein ensure a short but cancer-free existence for some people?
The scientists involved in this study say there are likely to be other proteins that impact both cancer and ageing, and the focus of research is now to catalogue the genes that make these proteins and find out which ones are the best candidates for drug therapies.