Virus Inside Gut Bacteria Linked to Colorectal Cancer, Study Finds

A Danish study identified a previously unknown bacteriophage inside the gut bacterium Bacteroides fragilis that is more commonly found in people with colorectal cancer. In a larger cohort, patients with cancer were about twice as likely to carry detectable levels of the phage, suggesting a virus–bacterium interaction may influence cancer risk and could inform future screening or treatment approaches. Causality has not been established, and more research is needed.