Led by Professor Yoshiaki Ito, the team found that when a gene, RUNX3, is disrupted, colorectal cancer can occur. RUNX3 is a gatekeeper gene which suppresses abnormal cell growth.

'For the first time, we found that inactivated RUNX3 occurs at the early stage of the cancer and is relatively easy to detect. This is significant as it is possible to reactivate the gene to slow down the cancerous growth,' said Prof Ito, a professor in medical oncology at the National University of Singapore's Yong Loo Lin School of Medicine, at a media conference yesterday.

In 2006, the team of 12 researchers found that the same gene plays a key role in gastric cancer. It is also present in other cancers of the bladder and breast.

The team, which has been studying RUNX3 for six years, comprises researchers from the medical school and the Agency for Science, Technology and Research's (A*Star) Institute of Molecular and Cell Biology (IMCB).

Their findings, published in the biomedical research journal Cancer Cell, move experts closer to identifying the right targets to develop therapeutic treatments in the fight against bowel cancer.

The medical school's dean, Professor John Wong, said: 'Prof Ito's research also lays the groundwork for a diagnostic kit for early detection.'

Understanding the causes of the disease also means a focused approach to treating it, instead of 'shotgun therapies', he added.

Colorectal cancer rates in Singapore are among the highest in the world. The disease has overtaken lung cancer as the top killer cancer among men, and is the second-highest cancer among women after breast cancer.

About 2,000 new cases are diagnosed each year.

The team's study of the gene in colon cancer involved both animal models and tissue samples from patients diagnosed with the cancer. The RUNX3 gene in all the human samples were 'switched off'.

Previous studies by research centres in Britain and the United States had found that flaws in another gatekeeper gene called adenomatous polyposis coli (APC) trigger development of most colorectal cancers.

Prof Ito's team showed that even when there is no flaw in the APC gene, cancer can still occur when the RUNX3 is not switched on.

Prof Ito said the good news is that changes to the RUNX3 gene seem to involve its function, and not its innate DNA sequence.

'This means its basic core remains intact, making it possible to be reactivated. We are now looking at how to do so and with which chemicals,' he said.

Until further advances, he said, the gold standard to detect the cancer is still colonoscopy, in which the entire large intestine can be examined through a scope.

The professor said that his team would study if the predisposition for the gene to be switched off is inherited.

He cautioned that it would be years before a diagnostic kit would be available for use by doctors.

juditht@sph.com.sg