Page last updated at 23:05 GMT, Tuesday, 10 June 2008 00:05 UK

Gene chemicals 'cancer warning'

Bowel cancer cell
Key chemical tags may drive cancer development

People vulnerable to cancer may have subtle differences in cell chemicals that could be detected before they actually develop the disease.

The UK Institute of Food Research team found these chemical "tags" in apparently normal cells taken from the intestines of bowel cancer patients.

The researchers said poor diet and lifestyle may prime these chemicals to activate cancer-causing genes.

The study appears in the British Journal of Cancer.

Cancer Research UK said that there could be other reasons for the chemical changes.

This represents a new way to identify defects that could eventually lead to cancer
Professor Ian Johnson
Institute of Food Research

Every cell in our body carries, in its DNA, all the genetic code for the creation and day-to-day running of our entire bodies.

However, in each cell type, various genes are switched on or off to allow it to perform its functions.

One of the ways this happens is by an "epigenetic code", a set of chemical tags attached to the DNA which label which genes should be on, or "expressed", and which should be turned off, or "silenced".

The development of cancer cells also relies on mistakes in this epigenetic code, switching on genes that cause abnormal growth, while silencing genes that would normally stop it.

Lifestyle question

At the Institute for Food Research in Norwich, researchers are investigating the possibility that, within seemingly healthy-looking tissue, faulty epigenetic tags may already be present as a warning that cancer is more likely.

They looked at the chemical makeup of "normal" cells lining the large intestine of bowel cancer patients, and found slight differences which could in theory render that person more vulnerable.

In other people, some of these differences happen alongside normal ageing, but the scientists believe that our lifestyles, such as diet, obesity and exercise could have an influence on the rate of change.

Professor Ian Johnson, who led the project, said: "We looked at changes in 18 genes that play a role in the very earliest stages of colorectal cancer, and 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."

No test yet

Henry Scowcroft, science information manager at Cancer Research UK, said the study was a "small but intriguing" piece in a larger, as yet unsolved, puzzle.

"It finds that 'normal' gut cells from people with bowel cancer contain 'abnormal' DNA regulation patterns, which the authors suggest may be used to detect cancer early.

"But these changes could also be a response to already having cancer, or to cancer treatment, and more studies will be needed to confirm this.

"This approach has a lot of potential, but there's a long way to go before doctors could use it as a predictive or diagnostic test."

Professor Nigel Brown, from the Biotechnology and Biological Sciences Research Council, which funded the research, said that epigenetics was a "relatively young" field of science, but was already providing answers.

"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."

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