Cancer-Resistant Mouse Aids Search for Treatments

A genetically engineered mouse that is resistant to bowel cancer may help scientists develop new methods to prevent and treat one the most common cancers in the developed world.

Professor Alan Clarke and a team of researchers at Cardiff University in Wales created the GM mouse by knocking out a gene called Mbd2 and breeding it with so-called “Min” mice which are highly susceptible to the disease. They found that the offspring that inherited the predisposition to cancer but did not have the gene lived twice as long as the other mice and had a ten-fold reduction in tumors. “We shut down tumor growth almost completely,” Clarke told a cancer conference on Wednesday. Mice without the gene were healthy, active and fertile but much less prone to cancer. The removal of the gene had no toxic effects and it seems to be only detrimental to tumor cells. “If it is as safe to dispense with Mbd2 activity in humans, then blocking it could become a powerful way to treat bowel cancer and protect high-risk groups from developing the disease,” Clarke added. More than 940,000 cases of bowel and rectal cancer occur each year worldwide. Studies have shown that a diet high in fats and animal protein raises the risk of developing the disease. It is inherited in about five percent of cases. Clarke and his colleagues, who presented their research at a meeting of the charity Cancer Research UK, are now developing a test to find a drug that will block the action of Mbd2. “We have identified in the mice a very good potential target,” he added. The scientists are also studying how Mbd2 works in normal cells and whether it may be involved in other cancers, including lymphoma and breast cancer. “This research is tremendously exciting because, if a similar gene is implicated to the same degree in human cancer, it raises the possibility of developing a safe, effective alternative in the prevention and treatment of bowel cancer,” said Professor Robert Souhami, the director of clinical and external affairs at Cancer Research UK. (Source: Cardiff University: Cancer Research UK: Reuters Health News: Patricia Reaney: May 2004)