If cells are stored in a confined space like a Petri dish, they will grow and divide until all of it is occupied, which is called “contact inhibition”. The protective mechanism is known to be linked with a certain gene called p27. However, naked mole rat cells have turned out to be much more “claustrophobic” than researchers expected. Cancer tumors are essentially normal cellular growth which has run amok, so this extra sensitivity must be protecting the rodent from developing the disease, they say.

Further study has revealed that naked mole rats have a second gene named p16, which stops cell growth when they have no free space. The scientists managed to mutate cells into growing tighter than normal, and so the level of protein expressed by this gene drop.

"It's very early to speculate about the implications, but if the effect of p16 can be simulated in humans, we might have a way to halt cancer before it starts," said Vera Gorbunova, associate professor of biology and a leading researcher in the study. Their findings have been published in the Proceedings of the National Academy of Sciences (PNAS).

For several years, Gorbunova and colleagues have been studying rodents from mice to beavers, and how they cope with risks associated with telomerase. The enzyme – the study of which won this year’s Nobel Prize for medicine – extends cells life expectancy by allowing them more divisions, but can also increase rates of cancer.

In short-living rodents, the risk is outweighed by better healing and vigor, but for longer-living ones, some protection against cancer is needed. The mechanism they found in naked mole rats is unique and is not used by any large mammals, Gorbunova says.

Researchers are now planning to study in detail this new contact inhibition pathway and find other molecules involved in it.