Glowing poop: McMaster researchers developing colorectal cancer test

Researchers from McMaster University in Hamilton are working on what they call simple, non-invasive test for colorectal cancer: glowing poop.

Biochemist Dr. Yingfu Li and gastroenterologist Dr. Bruno Salena say the test they’re developing under a grant from the Canadian Cancer Society is an innovative way to get more people checked for cancer.

“I find it very exciting as a clinician,” Salena said. “If we can produce a simple, cost-effective test here, the costs for a population are much less all around.”

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If we could offer a simpler test, you’d get more people receptive to this type of screening.- Dr. Yingfu Li, cancer researcher

To start the study, researchers are amassing a pool of as many as a quadrillion DNA sequences. With this massive pool, they plan to search for specific DNA enzymes that will glow in the feces of people with colorectal cancer. If they’re successful, the detection tool could one day be used in the doctor’s office as a simple, inexpensive test for cancer.

Colorectal cancer is the second leading cause of cancer deaths for men in Canada, behind lung cancer, and the third-leading cause of death among women, behind lung and breast cancer, according to Canadian Cancer Statistics 2014.

But doctors say when colon cancer is caught early, it’s 90 per cent treatable.

There are currently two at-home tests that can detect tiny amounts of blood in stool samples when cancer is present, but they can produce many false positives.

Getting more people screened

A colonoscopy is a more accurate test, but it’s invasive, expensive and not recommended for the general population until age 50, doctors say. The cancer society says anyone with risk factors for colon cancer, such as a "first-degree" relative with the disease, should work with their doctors to develop the plan that is right for them.

Li says he has first-hand understanding of the need for less invasive screening procedures. He recently turned 50, and had a colonoscopy – something that “wasn’t easy.”

“If we could offer a simpler test, you’d get more people receptive to this type of screening,” he said.

Both men are confident they’ll be able to find the DNA enzymes necessary to make this work. Li is in the middle of proving a similar process is possible in another study on Clostridium difficile (C. difficile). “That’s given us the confidence to think this will work,” he said.

Supporting research

Dr Siân Bevan, director of research for the Canadian Cancer Society, says the “serendipitous” collaboration of Li and Salena — they met playing golf — has allowed them to tackle an old problem in a new way.

“It’s a great example of the importance of supporting innovation in cancer research,” Bevan said. “In fact, in part because of the strength of the applications, this is the largest number of Innovation Grants we’ve funded since we launched the program.”

The two doctors applied for the cancer society Innovation Grant in July. So far, 51 grants totalling almost $10 million have been issued under the program.

“We’re very fortunate to receive this grant,” Li said.

Salena says researchers have already studied 30 colorectal cancer patients’ stool samples, and by next summer, they should have a panel of molecules that can be tested alongside them.

If the test works, there’s no reason the same system couldn’t be implemented to test other types of cancer, Salena says, like using a glowing urine sample to find prostate cancer.

“We’re really going to do our best to make this happen.”