"What's up doc?"
Naked mole rats
are immune to cancer

Researchers Check Suspicious Looking Mole (Rat)

November 04, 2009
by Jennifer Madison, DOTmed News Reporter
There is one species that's winning the rat race against cancer, and researchers are uncovering why the hairless animal is so superior. Scientists at the University of Rochester in New York are studying the naked mole rat, the only known animal immune to cancer; and they hope the buck-toothed creature will unlock long-standing mysteries surrounding the disease -- and help humans find a cure.

The naked mole rat is among several types of burrowing rodents, a diverse species widely used for scientific research. Their lifespan of up to 30 years is staggeringly long for the species. And three decades of life is certainly enough time for most animals to develop cancerous cells. However, unlike mice and humans -- two species often used in cancer research -- cancerous tumors have never been found in the mole rat.

The animal has a unique genetic defense against the disease according to head researcher Vera Gorbunova, associate professor of biology; her associate Andrei Seluanov, research professor of biology; and their colleagues at the university. The findings of their studies are shared in the October issue of The Proceedings of the National Academy of Sciences.

According to the study, the naked mole rat shares a gene with humans and many other animals called p27, which prevents the overcrowding among cells that can lead to cancer. However, researchers have now uncovered a second defense uniquely possessed by naked mole rats.

As part of the study, Gorbunova and her team attempted to mutate cells in the rodents in an effort to induce tumors. However, they found that the p16 gene found in the creatures provides a highly pronounced cancer-proof effect. Cells refused to replicate in the animals due to their evolved defense system, preventing overcrowding at a rate much earlier than in other animals. Gorbunova explains, "We realized that whatever was doing this was probably the same thing that prevented cancer from ever getting started in the mole rats."

Before stumbling upon the naked mole rat's cancer-proof system, Gorbunova and Seluanov investigated other rodent species around the world in an effort to better understand cancer and its effect. She recalls, "We were interested in comparative biology of aging and were studying short- and long-lived rodent species. (The) naked mole rat stood out by being an exceptionally long-lived and cancer-free rodent. We suspected that naked mole rats may use a novel anticancer mechanism that is not found in mice or humans."

Through their testing methods, any other species would have become cancerous. Gorbunova admits she was stunned by the findings, which she calls "a bit of a surprise."

However, she is hesitant to theorize how her research could affect cancer research in humans and other species. She explains, "It's very early to speculate about the implications." On expanding her research she adds, "We are working to identify the triggers of early contact inhibition with the hope of using those molecules to arrest the growth of cancer cells."