A team of US scientists announced on Friday that they have discovered a genetic trait that is present in 10 percent to 20 percent of patients with colorectal cancer.

The findings, published in the Aug. 15 issue of Science, strongly suggest that the trait is a major contributor to colorectal cancer risk and likely the most common cause of colorectal cancer to date.

If a person inherits this trait, which is dominant and clusters in families, the study found the lifetime risk of developing colorectal cancer is 50 percent, compared to 6 percent for the general population.

"This probably accounts for more colorectal cancers than all other gene mutations discovered thus far," said Boris Pasche of Northwestern University, a lead author of the paper.

"The reasonable expectation is this finding will save some lives," Pasche said. "We will be able to identify a larger number of individuals that are at risk of colorectal cancer and, in the long term, maybe decrease the cases of colorectal cancer and of people dying from it by being able to screen them more frequently."

Colorectal cancer is the second leading cause of cancer death in the United States About one-third of colorectal cancers are inherited.

The trait, which has been named TGFBR1 ASE, results in decreased production of a key receptor for TGF-beta, the most potent inhibitor of cell growth. With less of this vital protective substance to inhibit cell growth, colon cancer can more easily develop.

The findings, which are based on a Caucasian population, need to be confirmed in other studies and may show strong variation between ethnic groups, Pasche said.

Pasche expects that a clinical test will soon be developed that could be offered to families with a history of colorectal cancer and other individuals to determine whether they carry this mutation.

(Xinhua News Agency August 16, 2008)