Which statement best describes the cancer-associated phenotype of Fusobacterium spp?

• A. Anti-inflammatory and non-adhesive
• B. Non-pathogenic in the gut
• C. Pro-inflammatory, adhesive/invasive, and may promote pro-oncogenic effects
• D. Only affects metabolism

Answer: (C)

The cancer-associated phenotype of Fusobacterium spp is characterized by a pro-inflammatory, adhesive/invasive behavior that can promote tumor development and progression. In species like Fusobacterium nucleatum, adhesins such as FadA allow the bacteria to attach to and invade colonic epithelial cells, binding to E-cadherin and activating beta-catenin signaling. This drives transcription of oncogenic and proliferative genes, contributing to tumor growth. At the same time, the bacteria stimulate a pro-inflammatory environment by engaging pathways such as NF-κB and increasing cytokines like IL-6 and IL-8, which can recruit immune cells in a way that supports tumor progression and may dampen anti-tumor immunity. This combination—adhesive/invasive capacity plus pro-inflammatory, pro-oncogenic signaling—best describes their cancer-associated phenotype. It is not anti-inflammatory, not non-pathogenic, and its impact goes beyond metabolism to directly influence cancer signaling and the tumor microenvironment.