WEDNESDAY, June 11 (HealthDay News) -- Subtle changes in the DNA's chemical coding may make the bowel more susceptible to cancer by making the cells addicted to turning the switch on in abnormal genes, a new study suggests.

Scientists at the Institute of Food Research, who published their findings in the current issue of the British Journal of Cancer, are now looking at whether one's diet could affect these changes and possible ward off colorectal cancer.

The researchers made their discovery after observing methyl groups attached to DNA taken from the cells lining the large intestine of bowel cancer patients. These groups are part of the "epigenetic code," chemical tags on DNA molecules that determine whether individual genes are turned on or off. Mistakes in the epigenetic code are partially the reason behind the abnormal behavior of cancer cells, which tell certain genes to grow some types of cells while switching off other genes that would cause these abnormal cells to destroy themselves.

"We looked at changes in 18 genes that play a role in the very earliest stages of colorectal cancer," Ian Johnson, of the Institute of Food Research, said in a prepared statement. "We detected clear chemical differences in these genes in otherwise normal tissue in cancer patients. This represents a new way to identify defects that could eventually lead to cancer."

The IFR scientists, with support from two other groups, are now looking into whether epigenetic code mistakes occur in apparently normal tissues long before the appearance of a tumor. They are also investigating whether lifestyle factors such as diet, obesity and exercise can affect DNA methylation as people age. If so, this may give people some control over this part of their long-term health.

"Basic research in the relatively young field of epigenetics is already contributing to our understanding of human health. Understanding how epigenetic processes work to maintain healthy cells and tissues is the key to long-term health, because, as we see here, the breakdown of these normal processes may subsequently cause disease," Nigel Brown, director of science and technology for the Biotechnology and Biological Sciences Research Council, said in a prepared statement. His organization is one of the group's supporting the IFR's study into diet and bowel cancer.

More information

The U.S. National Library of Medicine has more about colorectal cancer .

-- Kevin McKeever

SOURCE: Norwich BioScience Institutes, news release, June 10, 2008

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