Gene Could Link Obesity, Colon Cancer

By Steven Reinberg
HealthDay Reporter
Tuesday, September 30, 2008; 4:00 PM

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TUESDAY, Sept. 30 (HealthDay News) -- Researchers have uncovered a genetic link between obesity and the risk for colon cancer. The discovery could lead to greater accuracy in predicting who is at risk for the disease, experts say.

Research has suggested that colon cancer risk rises with increasing weight, but this finding points to a genetic reason for the link.

"We have discovered that a genetic variant of the adiponectin gene, called ADIPOQ, is associated with colon cancer risk," said lead researcher Dr. Boris Pasche, director of the division of hematology and oncology at the Comprehensive Cancer Center of the University of Alabama at Birmingham. "This genetic variant may identify individuals who have a higher risk to develop colorectal cancer," he said.

The report was published in the Oct. 1 issue of the Journal of the American Medical Association.

For the study, Pasche's team focused on ADIPOQ. This gene promotes the formation of a fat hormone called adiponectin. People who inherit a common variant of the gene have up to a 30 percent lower risk of colon cancer compared with people without this gene variant, the study found.

On the other hand, the researchers believe that people who do not have this gene variant, or those who have high levels of adiponectin in their blood, may be at a slightly increased risk for colon cancer and could benefit from early screening for the disease.

"Adiponectin, a hormone exclusively secreted by the adipose [fat] tissue, is now genetically linked with colorectal cancer," Pasche said. "This is the first evidence that genetic variants of a 'fat hormone' affect risk of colorectal cancer," he said.

Whether people without this gene variant can reduce their risk of colon cancer through diet and exercise isn't clear, the researchers noted.

"This adds a little bit more to our understanding of one place where genetics plays a role in colon cancer development," said Dr. Durado Brooks, director of colon and prostate cancer prevention programs at the American Cancer Society. "It helps point us in some more specific directions; it adds another piece to the puzzle," he said.