Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in Canada, and rates are rising among younger adults, yet we still don’t fully understand what drives this disease.
A team of researchers at the University of Toronto has received support through a major cancer prevention initiative led by the Canadian Institutes of Health Research to investigate one potential contributor called pks+ E.coli, a naturally occurring bacteria in the gut that may promote colorectal cancer.
With $1 million from the Terry Fox Research Institute, and $1 million from the Canadian Cancer Society, the team will spend the next five years exploring how dietary interventions can counteract this cancer-causing microbe. More specifically, they will focus on high-fibre diets, seeking to understand which types of fibre most effectively reduce this harmful microbe and reduce colorectal cancer risk.
Their previous work in mice has shown that this specific E.coli bacteria, which is present in roughly 20 per cent of healthy humans, can promote colorectal cancer when they’re fed a common weight loss diet that is low in carbohydrates and fibre. The bacteria also accelerated tumour development in mice carrying mutations in a DNA repair gene (the Mismatch Repair gene), which is commonly mutated in patients with colorectal cancer.
In this project, the team will test potential preventions strategies. Using animal models, they aim to identify which dietary fibres can protect against colorectal cancer in mice. They will then translate these findings into humans, exploring whether certain types of fibre can reduce this harmful gut bacteria in people at higher risk of developing colorectal cancer, including those with inflammatory bowel disease or Lynch syndrome. In addition, the team will assess whether interfering with the bacteria’s respiration can limit its growth in both mice and humans.
“As an immunologist, joining the Terry Fox research community has been a career-long ambition,” says Dr. Alberto Martin, project lead and professor at the University of Toronto. “This network represents an elite group of scientists dedicated to the singular goal of preventing and treating cancer. I am honored to have our work selected for this cancer prevention initiative and look forward to translating our proposed research plan into action.”
By testing these findings in humans and building the evidence needed for future clinical trials, the team hopes to inform practical approaches to colorectal cancer prevention.
Ultimately, this work could help shape new strategies around diet and lifestyle, improve screening for individuals at higher risk and support more personalized prevention efforts, all aimed at reducing the burden of colorectal cancer before it begins.