With its wrinkled skin and bucked teeth, the naked mole rat isn't going to win any beauty contests. But the burrowing, desert rodent is exceptional in another way: It doesn't get cancer. The naked mole rat's cells hate to be crowded, it turns out, so they stop growing before they can form tumors. The details could someday lead to a new strategy for treating cancer in people. In search of clues to aging, cell biologists Vera Gorbunova, Andrei Seluanov, and colleagues at the University of Rochester have been comparing rodents that vary in size and life span, from mice to beavers. The naked mole rat stands out because it's small yet can live more than 28 years–seven times as long as a house mouse. Resistance to cancer could be a major factor; whereas most laboratory mice and rats die from the disease, it has never been observed in naked mole rats.
Gorbunova's team looked at the mole rat's cells for an answer. Normal human and mouse cells will grow and divide in a petri dish until they mash tightly against one another in a single, dense layer–a mechanism known as “contact inhibition.” Naked mole rat cells are even more sensitive to their neighbors, the researchers found. The cells stop growing as soon as they touch. The strategy likely helps keep the rodents cancer-free, as contact inhibition fails in cancerous cells, causing them to pile up.