The gut bacterium Bacteroides fragilis has long presented researchers with a paradox. It has been associated with colorectal cancer, yet it also lives quite happily in most healthy people. A new study from a Danish research team offers a possible clue. When they looked beyond the bacterium itself and into its genome, they found a previously unknown virus embedded within it – one that was significantly more common in cancer patients.
Colorectal cancer is the third most common cancer worldwide and is responsible for the second highest number of cancer-related deaths. Up to 80% of colorectal cancer cases are attributed to environmental factors, with one of the most significant being the gut microbiome – the collection of bacteria, fungi and viruses that live in the human gut.
