Study Finds Link Between Colon Cancer, Bacteria

The Poopy Lab does have a distinctive smell, but you get used to it, say these U of G researchers - photo credit: the Portico

GUELPH, Ontario October 20, 2011 - University of Guelph - News Release

A research team including University of Guelph scientists has found for the first time that a specific gut microbe is connected to colorectal cancer.

The finding may help researchers design a simpler screening tool for diagnosing tumours and, ultimately, find a more effective way to prevent one of the most deadly kinds of cancer, said U of G Prof. Emma Allen-Vercoe, Department of Molecular and Cellular Biology.

Two research teams published papers online this week in Genome Research that identify a link between Fusobacterium nucleatum and colon cancer. This particular microbe is found more often in colon cancer tissue than in normal tissue, said Allen-Vercoe.

She co-authored one of those papers along with PhD student Jaclyn Strauss and researchers at Simon Fraser University in British Columbia and the B.C. Cancer Agency. The team was led by B.C. scientist Robert Holt.

“I think this is really exciting,” said Allen-Vercoe. “If we can show that Fusobacterium is involved directly or indirectly, I think there’s a lot of potential to develop interventions such as a vaccine to reduce colonization by this bacterium.”

She cautioned that any vaccine or other treatment may be years or decades away. Scientists still don’t know whether the microbe actually causes the disease or is only associated with it.

But they hope doctors might be able to use the microbe to screen for colon cancer, perhaps by testing blood or stool samples instead of subjecting many people to complicated and invasive colonoscopies.

In 2011, an estimated 22,200 Canadians will be diagnosed with colorectal cancer and 8,900 will die of it, according to Canadian Cancer Society statistics. It’s the second leading cause of cancer death among men and women combined.

F. nucleatum is a known pathogen, but it is rare and had not been associated earlier with cancer, said Holt.

In her Guelph microbiology lab, Allen-Vercoe cultured a strain of the bacterium from colon tumour biopsy samples. Her collaborators subsequently determined the strain’s genetic sequence.

Earlier, her U of G team found evidence that patients with inflammatory bowel disease have more F. nucleatum – and more virulent strains -- in their gut than people without the ailment.

Allen-Vercoe is one of only a few Canadian researchers on an international project cataloguing the genomes of all microbes found on or in the human body.