Fusobacterium nucleatum and cancer. Periodontology 2000 Accumulating evidence demonstrates that the oral pathobiont Fusobacterium nucleatum is involved in the progression of an increasing number of tumors types. Thus far, the mechanisms underlying tumor exacerbation by F. nucleatum include the enhancement of proliferation, establishment of a tumor-promoting immune environment, induction of chemoresistance, and the activation of immune checkpoints. This review focuses on the mechanisms that mediate tumor-specific colonization by fusobacteria. Elucidating the mechanisms mediating fusobacterial tumor tropism and promotion might provide new insights for the development of novel approaches for tumor detection and treatment. 10.1111/prd.12426