Researchers find DNA link between colon cancer, obesity

People with a common genetic variation in their fat cells may have some protection against developing colon cancer, according to a study that provides the first DNA link between the deadly tumors and obesity.

Fat cells produce adiponectin, a hormone that appears at lower levels in people who are obese or have diabetes. It also can be found within the colon, where it seems to help regulate cell growth. Obesity and colon cancer are known to have genetic ties, so the researchers homed in on the common ground between the two conditions.

The study, comprised of reviews of colon cancer patients and healthy comparisons in New York and Chicago, found those with a variation in the adiponectin gene were almost 30 percent less likely to have the tumors. The results in the Journal of the American Medical Association may one day help doctors fine-tune screening for colon cancer, the second deadliest malignancy after lung cancer, the researchers said.

"If you enhance your ability to screen these higher-risk individuals, you may have a greater chance of picking up the disease at an early stage and preventing them from dying of colon cancer," said lead investigator Boris Pasche, director of hematology and oncology at the University of Alabama. "That is the hope."

Colorectal cancer is diagnosed in more than 100,000 people in the U.S. each year, making it the fourth most common tumor in Americans, according to the American Cancer Society. Nearly 50,000 Americans die from it annually, even though the disease can be prevented if caught early when precancerous lesions are first developing. Fewer than half of people who should get screened each year actually undergo the tests, research shows.

Additional work is needed to determine if genetic tests to help identify people who need earlier, more frequent screening can save lives, the investigators said.