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 prostate 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.
Brooks does not believe that the finding is definitive, however. “It
supports some of the other work that has already been done, identifying
this particular gene region with colorectal cancer,” he said.
The finding does help clarify one element linking obesity and colon
cancer, but “there is no clinical application to this finding in the
immediate future,” Brooks said. “I don’t think we would alter any
recommendation, other than encouraging people to maintain a healthy
weight.”
Dr. Georgia Wiesner, a cancer geneticist at University Hospitals‘ Case
Medical Center in Cleveland, agreed.
“I’d love to say that any time we find a new gene that identifies risk
or alters risk we would be able to put that into a new drug treatment or
at least identify people who are more at risk,” Wiesner said. “But in this
study, it might just tease out the pathogenesis of disease,” she said.
It’s already known that people who are obese have a higher risk for
colon cancer, Wiesner said. “I don’t know that telling somebody they might
have a specific marker is really going to alter what they are going to
do,” she said. “It doesn’t mean that these people don’t need regular
screening.”
More information
For more on colon cancer, visit the American Cancer Society.
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