The Potential of Colonic Tumor Tissue Fusobacterium nucleatum to Predict Staging and Its Interplay with Oral Abundance in Colon Cancer Patients

SIMPLE SUMMARY: Colon cancer (CC) is a multifactorial disease, and complex interactions among the gut microbiota, inflammation and environmental exposures are needed for colorectal carcinogenesis. Oral Fusobacterium nucleatum (Fn) and Porphyromonas gingivalis (Pg) are predominant pathogens involved in periodontitis and can migrate from the oral cavity to other districts of the body, including the colon. The aim of the study was to analyze the link between oral Fn and Pg, oral health, diet, lifestyle and risk of CC. The Fn quantity was greater in the oral cavity than in CC, and its concentration influenced the Fn quantity in CC tissue. The meat consumption was related to intestinal Fn. Instead, Pg was not associated with CC. The Fn abundance in CC tissue could predict cancer staging, becoming a potential biomarker to find out the prognosis of colic cancer patients. ABSTRACT: Background. Intestinal microbiota dysbiosis may enhance the carcinogenicity of colon cancer (CC) by the proliferation and differentiation of epithelial cells. Oral Fusobacterium nucleatum (Fn) and Porphyromonas gingivalis (Pg) have the ability to invade the gut epithelium, promoting tumor progression. The aim of the study was to assess whether the abundance of these odontopathogenic bacteria was associated with colon cancer. We also investigated how lifestyle factors could influence the oral Fn and Pg abundance and CC. Methods. Thirty-six CC patients were included in the study to assess the Pg and Fn oral and colon tissue abundance by qPCR. Oral health data, food habits and lifestyles were also recorded. Results. Patients had a greater quantity of Fn in the oral cavity than matched CC and adjacent non-neoplastic mucosa (adj t) tissues (p = 0.004 and p < 0.001). Instead, Pg was not significantly detected in colonic tissues. There was an association between the Fn quantity in the oral and CC tissue and a statistically significant relation between the Fn abundance in adenocarcinoma (ADK) and staging (p = 0.016). The statistical analysis revealed a tendency towards a greater Fn quantity in CC (p = 0.073, η(2)(p) = 0.12) for high-meat consumers. Conclusion. In our study, Pg was absent in colon tissues but was correlated with the oral inflammation gingival and plaque indices. For the first time, there was evidence that the Fn oral concentration can influence colon tissue concentrations and predict CC prognosis.