Danish scientists have drawn attention to a newly discovered possible cause of colon cancer. According to them, the common intestinal bacteria Bacteroides fragilis, which is found in most people’s intestines and is usually considered harmless, could play a role. However, it is carcinogenic only if it is itself infected with a virus.
The Danish authors reported that this bacterium may contain a previously unknown virus that appears significantly more frequently in patients with colon cancer. The researchers analyzed the gut bacteria of more than eight hundred people, half of whom had been diagnosed with colorectal cancer.
From the results, it is clear that in patients with this disease, the bacterium Bacteroides fragilis was infected with the virus approximately twice as often as in people without cancer. Scientists believe that this infection can change the behavior of the bacteria and trigger processes that increase the risk of tumor formation.
“These findings suggest a cooperation between bacteria and their viruses that can influence the development of diseases. If confirmed, it may promote earlier detection of colorectal cancer and lead to new ways to treat and prevent the disease.” thinks molecular biologist and lead author of the study Fleming Damgaard.
Colon cancer is one of the most widespread cancers in the world. Worldwide, it is the third most common type of cancer and the second most common cause of cancer-related death.
Scientists remind that bacteria can be infected by a special type of virus called bacteriophage. In some cases, they can integrate into their genetic information and create a virus hidden inside the bacterium. Such an infection can change the behavior of the bacterium. A similar mechanism is known, for example, in the case of cholera or diphtheria, when a virus-infected bacterium produces disease-causing toxins.
However, the Danish authors point out that their research has so far only shown an association, not a direct cause. They emphasize that more research is needed to confirm the results. At the same time, the researchers remind that the increase in cases of colon cancer in younger people may also be related to changes in the intestinal microbiome, increasing obesity, unhealthy diet or environmental influences.
Some diseases also increase the risk, for example, inflammatory bowel disease, which can cause chronic inflammation and, according to studies, increases the likelihood of developing cancer up to three times.
