Colorectal cancer diagnoses are on the rise for people under 55. A recent American Cancer Society (ACS) report states that cases are increasing by 1% to 2% annually among people in that age group.

Alarmingly, the ACS reports colorectal cancer is the leading cause of cancer death in men under 50 and the second in women under 50, and research indicates that lifestyle changes over several decades may be to blame.

Cancer Center at Illinois (CCIL) researcher H. Rex Gaskins has spent nearly three decades exploring how colonic bacteria may contribute to the development and progression of colorectal cancer, and how lifestyle modifications may offer preventative benefits.

CCIL researcher H. Rex Gaskins

“People are just waking up to it. The whole story has been compiled, so seeing the parts come together is rewarding,” said Gaskins.

That story began years ago when Gaskins and colleagues demonstrated that the human colon harbors bacteria that produce hydrogen sulfide.

“Every human has these bacteria. What we think is happening is that the sulfide is serving a defensive role, and that’s why it’s beneficial for us to harbor these toxin-producing bacteria at low levels,” said Gaskins. “When hydrogen sulfide is at a low level, it kills other bacteria to keep them away from the epithelial surface of the colon.”

According to Gaskins, problems arise when there is a high hydrogen sulfide concentration because the potent genotoxin can damage DNA. Those findings led to the determination that hydrogen sulfide can be an environmental trigger of colorectal cancer. Identifying that genotoxin played a key role in later studies focused on how a person’s diet can impact biomarkers.

Gaskins and colleagues studied the Zulu community in South Africa, whose diet is primarily plant-based. For two weeks, the group ate a diet rich in meat and animal products, while a group of African Americans in the U.S. switched to a plant-based diet.

The results?

“If we put the Americans on an African diet, we saw a reduction in markers of colorectal cancer risk. If we put the Africans on an American diet, we saw an increase,” said Gaskins. “I think watching one’s diet is crucial. That’s not to say if you eat a lot of meat, you’re going to get colorectal cancer – not at all. It also depends on a person’s predisposing genetic background, but it emphasizes the importance of a balanced diet.”

Those findings motivated Gaskins to understand why African Americans have an increased risk of developing colorectal cancer which led to another study with pivotal findings.

“We were interested in determining to what extent the microbiota that resides in the colon can be different between different races,” said Gaskins. “What we observed was surprising. Sulfidogenic bacteria are more abundant in African Americans. We saw ten times higher colonization in African Americans with these sulfidogenic bacteria than in non-Hispanic whites – and that was independent of disease status. In other words, we saw it in the healthy controls, we saw it in the colorectal cancer patients.”

Gaskins has continued his work in these areas over the years, and these studies are just a few of his large body of research. It’s work like his that drives forward the CCIL’s mission to help cancer patients, survivors, and their families. His investigations are a testament to the crucial part research plays in helping people understand their risk factors while giving doctors and other scientists vital information to advance detection methods and treatment options.

New statistics on colorectal cancer have led to a push in screening reminders, especially during National Colorectal Cancer Awareness Month. To learn more about how you can protect yourself, click here.

Editor’s Notes:

H. Rex Gaskins is the Keith W. and Sara M. Kelley Professor of Immunophysiology and is affiliated with the following departments: Animal Sciences, Biomedical and Translational Sciences, Pathobiology, Division of Nutritional Sciences, Cancer Center at Illinois, and the Carl R. Woese Institute for Genomic Biology. He is the Deputy Director of the Tissue Microenvironment Training Program.

This story was written by Jessica Clegg, CCIL Communications Team