Fusobacterium nucleatum: ecology, pathogenesis and clinical implications.

Fusobacterium nucleatum, a commensal microorganism and opportunistic pathogen (a pathobiont), has emerged as a key player in both local and systemic diseases. In humans, F. nucleatum is found in the oral microbiota, but under certain conditions, it can spread to other ecological niches within the body, such as the gut microbiota. Importantly, F. nucleatum has a pathogenic role in periodontal disease, inflammatory bowel disease and various cancers, particularly colorectal cancer. F. nucleatum can promote oncogenesis via several mechanisms, including virulence factors, chronic inflammation, immune evasion and direct interactions with tumour cells. The strong link between this pathobiont microorganism and cancer has led to the emergence of several potential diagnostic strategies and possible therapeutic interventions. Given its increasing association with cancer progression and poor clinical outcomes, understanding the role of F. nucleatum in disease treatment offers critical insights for future research and clinical applications. This Review underscores the importance of F. nucleatum in microbiology, oncology and translational medicine.