Human oral microbiome dysbiosis as a novel tool for detecting noninvasive biomarkers for colorectal cancer.

Abstract

23 Background: The oral microbiome may play an important role in colorectal carcinogenesis. However, few studies have investigated the association between oral microbiome and the development of colorectal cancer (CRC). We aimed to investigate whether oral health–colorectal tumor association has an underlying microbial basis, in the quest for novel non-invasive biomarkers for CRC. Methods: We collected oral swab samples from 161 patients with CRC, 34 patients with colorectal adenoma (CRA), and 58 healthy volunteers. The oral microbiota was assessed using 16S rRNA sequencing. The oral microbiome was characterized, microbial markers were identified, and colorectal tumor (CRA and CRC) classifiers were constructed and validated. Results: Oral microbial composition and diversity were significantly different among the three groups; the CRA group had the highest diversity. Analysis of the functional potential of oral microbiota demonstrated that the pathway involving cell motility was overrepresented in the CRA and CRC groups relative to that in the healthy controls. Moreover, a random forest model was constructed based on oral microbial markers, which could distinguish the colorectal tumor groups from the healthy controls and achieve a powerful classification potential in the discovery and validation cohorts. Conclusions: This study suggests a potential association between oral microbiome dysbiosis and colorectal cancer. Oral microbiota-based biomarkers may be helpful in predicting the risk of developing CRA and CRC.