Involvement ofFusobacteriumSpecies in Oral Cancer Progression: A Literature Review Including Other Types of Cancer

Chronic inflammation caused by infections has been suggested to be one of the most important cause of cancers. It has recently been shown that there is correlation between intestinal bacteria and cancer development including metastasis. As over 700 bacterial species exist in an oral cavity, it has been concerning that bacterial infection may cause oral cancer. However, the role of bacteria regarding tumorigenesis of oral cancer remains unclear. Several papers have shown thatFusobacteriumspecies deriving the oral cavities, especially, play a crucial role for the development of colorectal and esophageal cancer.F. nucleatumis a well-known oral bacterium involved in formation of typical dental plaque on human teeth and causing periodontal diseases. The greatest characteristic ofF. nucleatumis its ability to adhere to various bacteria and host cells. Interestingly,F. nucleatumis frequently detected in oral cancer tissues. Moreover, detection ofF. nucleatumis correlated with the clinical stage of oral cancer. Although the detailed mechanism is still unclear,Fusobacteriumspecies have been suggested to be associated with cell adhesion, tumorigenesis, epithelial-to-mesenchymal transition, inflammasomes, cell cycle, etc. in oral cancer. In this review, we introduce the reports focused on the association ofFusobacteriumspecies with cancer development and progression including oral, esophageal, and colon cancers.