Some Periodontal Bacteria May Be Cancer-Promoting

Xiaodan Mai MBBS University at Buffalo, The State University of New York Buffalo, Interview with:
Xiaodan Mai MBBS
University at Buffalo, The State University of New York
Buffalo, NY

MedicalResearch: What is the background for this study? What are the main findings?

Response: Periodontal disease is a condition that is highly prevalent amongst the elderly, and is characterized by chronic polymicrobial infection and inflammation of gum tissue. Periodontal disease has been associated with increased cancer risk, and these findings may be partially explained by extra-oral translocation of subgingival bacteria that subsequently modulates host cell environment and function. However, there is limited research on whether the presence of certain subgingival bacteria influences cancer risk. .

Oral bacteria have been categorized into color-coded complexes by their timing of colonization and strength of association with periodontal disease. Using data from an ancillary study of the Women’s Health Initiative conducted in Buffalo, New York (a cohort of 1300 postmenopausal women), we therefore investigated the associations between the presence of three early-colonizing periodontal pathogens (Fusobacterium nucleatum, Prevotella intermedia, and Campylobacter rectus, i.e., “orange complex” bacteria moderately associated with PD), the presence of two late-colonizing periodontal pathogens (Porphyromonas gingivalis, Tannerella forsythia, i.e., “red complex” bacteria strongly associated with PD) in dental plaque and cancer risk. We found borderline associations between presence of any early-colonizing pathogens and increased risk of total cancer and lung cancer. Individual pathogens were not associated with total cancer or site-specific cancers when analyzed singly. Presence of any pathogens or presence of any late-colonizing pathogens was not associated with total or site-specific cancer.

MedicalResearch: What should clinicians and patients take away from your report?

Response: Over 700 microorganisms have been detected in the oral cavity, and thus this study provided only a snapshot of the complex role of the oral microbiome in carcinogenesis. Interpretation of the results is further limited by the small number of incident cancer cases. Nonetheless, the borderline positive relationships found between the presence of early-colonizing periodontal pathogens and cancer risk suggest that certain bacterial species may be involved in cancer-promoting events or may serve as non-invasive indicators of malignant potential.

MedicalResearch: What recommendations do you have for future research as a result of this study?

Response: Research utilizing a larger cohort with a more comprehensive assessment of the presence and abundance of oral bacteria is needed to evaluate the associations among periodontal disease, the oral microbiome, and risk of total cancer as well as site-specific cancers. In addition, as a more direct test of the “mobile microbiome” hypothesis, we are currently investigating whether similar bacterial species are found in tumor tissues and in the subgingival plaques of the same cancer patients.


Presented at the 2015 AACR Meeting in Philadelphia

Pathogenic oral bacteria and risk of incident cancer in postmenopausal women: The Buffalo OsteoPerio Study

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Xiaodan Mai MBBS, University at Buffalo The State University of New York, & Buffalo, NY (2015). Some Periodontal Bacteria May Be Cancer-Promoting