A gene that significantly increases the risk of bowel cancer in people who carry it has been discovered by a team of international researchers, a breakthrough that may play a significant role in how people are screened for the disease.

Research teams from Canada, Britain and the United States, who compiled their respective reports in the Assessment of Risk for Colorectal Tumours in Canada (ARCTIC) project, have identified a genetic variation on chromosome 8 that is linked to colon cancer.

People who carry rs6983267 variant gene, which is located on a region of chromosome 8 called 8q24, have about a 20 percent higher risk of developing a colorectal malignancy compared to those who do not carry this variant, the researchers said.

To reach their findings, which were published online on Sunday by the journal Nature Genetics, the scientists analyzed DNA from more than 10,000 people, including 2,400 Ontarians from the Ontario Familial Colorectal Cancer Registry. Then, they compared key differences in DNA against genes from healthy controls.

The three projects that covered the people from Ontario, Newfoundland and Labrador, Scotland, France, Seattle and Britain, as well as five ethnic subpopulations of the United States – Americans of African, Japanese, Hawaiian, Latino and European heritage have found the same link in populations.

Researchers concluded in their findings that lifetime risk of developing bowel cancer is one in 20 for the general population, but this increases to one in 16 for people who have inherited the genetic variant.

Earlier research on Chromosome 8, a region of the genome recently linked to breast and prostate cancer, has indicated this gene’s link with other forms of cancers like breast and prostate cancer. Now the researchers have linked the gene to colorectal cancer in a surprising large number of people.

"At least to our knowledge this is the first common genetic risk factor that has been reproducibly associated with risk of multiple cancers," said American paper’s lead author Christopher Haiman of the Keck School of Medicine at the University of Southern California.

Dr. Malcolm Dunlop of Cancer Research UK and the University of Edinburgh, Scotland was the co-principal investigator of British report, while Dr. Tom Hudson, president and scientific director of the Ontario Institute for Cancer Research, and Dr. Brent Zanke, scientist at Cancer Care Ontario, were the lead authors of Canadian research.

Researchers hope the recent findings could help scientists design a test for a combination of genes to identify those most at risk of developing colorectal cancer, improving prevention and diagnosis.

"This discovery will lead to better understanding of colorectal cancer biology and the cause of this disease," said Dr. Hudson. "This information can be used to identify those at risk of colorectal cancer and direct them to screening at an earlier age."

Meanwhile, a separate study led by a consortium from Israel, Spain and the United States also linked the genetic variations on 8q24 to high risk of colon cancer. The findings were published in the July issue of Cancer Biology and Therapy.

Colon cancer (medically known as Colorectal cancer) is the cancerous growth in the colon, rectum or the appendix. As per figures of the World Health Organization, it is reported as the fourth most deadly malignancy globally, killing nearly 6,55,000 people annually.

According to the American Cancer Society, bowel cancer kills more than 51,000 Americans each year, while some 35,000 people are diagnosed with bowel cancer in the UK each year. In Britain, it is the third most common cancer after breast and lung, with an annual death rate of 16,100. Genetic defect is accountable for nearly one in 10 cases of bowel cancer in the UK.

As per the Canadian Cancer Society estimates, nearly 20,800 Canadians will be diagnosed with colon cancer this year and of which 8,700 will eventually die of the disease. It is the fourth most common form of cancer in Canada, and the second most lethal, after lung cancer.