A previously unknown virus is showing up frequently in colorectal cancer patients, study finds

A previously unknown virus is showing up frequently in colorectal cancer patients, study finds

Can viruses in the gut cause colorectal cancer

Synopsis

Gut virus in colorectal cancer patients: Scientists have uncovered a new virus within a common gut bacterium, Bacteroides fragilis. This virus appears more often in individuals diagnosed with colorectal cancer. This discovery offers a potential new way to understand the disease. Researchers are exploring if stool tests for these viruses could help assess cancer risk in the future.

Gut virus in colorectal cancer patients: For years, scientists have known that the gut plays an important role in health and disease. In colorectal cancer, one bacterium in particular, Bacteroides fragilis, has repeatedly appeared in research, but there has always been a mystery: the same bacterium is also found in most healthy people.

Colorectal Cancer Risk: Why Bacteroides fragilis Has Puzzled Scientists for Years

Now, researchers from the University of Southern Denmark and Odense University Hospital believe they may have uncovered a missing piece of that puzzle. Instead of focusing only on the bacterium itself, they looked inside it and found a previously undescribed virus that appears more frequently in patients with colorectal cancer, as per a report.

Flemming Damgaard, medical doctor and PhD at the Department of Clinical Microbiology, said that, "It has been a paradox that we repeatedly find the same bacterium in connection with colorectal cancer, while at the same time it is a completely normal part of the gut in healthy people," as quoted in an SDU report.

Inside the Gut: How Bacteriophages May Influence Cancer Development

The team investigated whether differences might exist within the bacterium. What they discovered was a virus known as a bacteriophage, a virus that lives inside bacteria. This particular virus had not been described before and was more commonly found in patients who later developed colorectal cancer.

Damgaard pointed out that, It is not just the bacterium itself that seems interesting. It is the bacterium in interaction with the virus it carries," as quoted by SDU.

Danish Population Study Uncovers Viral Pattern

The research began in Denmark, drawing on data from a large population study involving around two million citizens. Researchers focused on patients who had experienced a serious bloodstream infection caused by Bacteroides fragilis. A smaller group of these patients were diagnosed with colorectal cancer within weeks.

When the scientists analysed the genetic material of the bacteria from patients with and without cancer, they noticed a clear pattern: bacteria from cancer patients were more often infected with specific viruses.

International Data Confirms Virus Association in 877 Patients

To see if the finding held up beyond Denmark, the team examined stool samples from 877 individuals across Europe, the United States and Asia. Again, they found that people with colorectal cancer were approximately twice as likely to have traces of these viruses in their gut.

Damgaard said, "It was important for us to examine whether the association could be reproduced in completely independent data," as quoted by SDU.

Statistical Link Found Between Gut Virus and Colorectal Cancer

The researchers stress that the study shows a statistical association, not proof that the virus causes cancer. Damgaard said, “We do not yet know whether the virus is a contributing cause, or whether it is simply a sign that something else in the gut has changed,” as quoted by SDU.

Understanding the Role of the Gut Microbiome in Cancer

Colorectal cancer is one of the most common cancers in the Western world, and up to 80 per cent of the risk is linked to environmental factors. The gut microbiome, the vast ecosystem of microorganisms living in the digestive tract, is believed to be one of the most important influences.

Because the gut contains thousands of bacterial species and even more genetic variation, pinpointing specific causes has been challenging. Damgaard compared earlier efforts to “looking for a needle in a haystack.” By shifting focus to viruses living inside bacteria, the team hopes to better understand what distinguishes healthy individuals from those who develop disease.

Could Stool Testing Detect Cancer-Linked Viruses in the Future

In preliminary analyses, selected viral sequences were able to identify around 40 per cent of cancer cases, while most healthy individuals did not carry them. Researchers suggest that, in the future, stool tests might screen for these viruses to help assess colorectal cancer risk.

FAQs

What did researchers discover?
They identified a previously undescribed virus inside a common gut bacterium linked to colorectal cancer.

What is Bacteroides fragilis?
It is a common gut bacterium found in most healthy individuals but also associated with colorectal cancer.

Article taken from, copyright belongs to : https://economictimes.indiatimes.com/news/international/us/a-previously-unknown-virus-is-showing-up-frequently-in-colorectal-cancer-patients-study-finds/articleshow/128650881.cms?from=mdr