Cancer Immunity

Naked mole rats are special. They have an "immunity" to cancer. Or at least a high resistance to it as scientists haven't found evidence of it. These hair-less rodents live up to 28 years, which is the longest for any rodent.

Biologists at the Unversity of Rochester believe they have found the reason. The findings show that the mole rat’s cells express a gene called p16 that makes the cells “claustrophobic,” stopping the cells’ proliferation when too many of them crowd together, cutting off runaway growth before it can start. The effect of p16 is so pronounced that when researchers mutated the cells to induce a tumor, the cells’ growth barely changed, whereas regular mouse cells became fully cancerous.
The reason, the researchers discovered, is that naked mole rat cells rely on two proteins--named p27 and p16--to stop cell growth when they touch, whereas human and mouse cells rely mainly on p27. "They use an additional checkpoint," says Gorbunova, whose study appears in the Proceedings of the National Academy of Sciences (PNAS). The additional level of protection may explain how the rodents remain cancer-free for their entire lives.


Sources:
http://www.neatorama.com/2009/10/27/naked-mole-rats-immune-to-cancer/
http://www.the-scientist.com/blog/display/56123/
http://news.sciencemag.org/sciencenow/2009/10/26-02.html