Fusobacterium nucleatum is an unlikely candidate for a cancer-instigating microbe. For years, F nucleatum has been regarded as a common constituent of the commensal oral microbiome and recognized as one of many different microbes associated with gingivitis and periodontitis. What has set F nucleatum apart is extreme strain-to-strain variation in its genotype, fusiform morphology, and adhesive and invasive properties.1,2 The increasingly frequent reports of associations of F nucleatum nonoral pathologies, ranging from gastrointestinal abscesses and acute appendicitis to intra-amniotic infection, and most recently colorectal,3–6 pancreatic,7 and oral cancers,8 have raised the alert level of F nucleatum to that of an emerging pathogen.