Oral Microbiome Composition Reflects Prospective Risk for Esophageal Cancers

Bacteria may play a role in esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC), although evidence is limited to cross-sectional studies. In this study, we examined the relationship of oral microbiota with EAC and ESCC risk in a prospective study nested in two cohorts. Oral bacteria were assessed using 16S rRNA gene sequencing in prediagnostic mouthwash samples from <i>n</i> = 81/160 EAC and <i>n</i> = 25/50 ESCC cases/matched controls. Findings were largely consistent across both cohorts. Metagenome content was predicted using PiCRUST. We examined associations between centered log-ratio transformed taxon or functional pathway abundances and risk using conditional logistic regression adjusting for BMI, smoking, and alcohol. We found the periodontal pathogen <i>Tannerella forsythia</i> to be associated with higher risk of EAC. Furthermore, we found that depletion of the commensal genus <i>Neisseria</i> and the species <i>Streptococcus pneumoniae</i> was associated with lower EAC risk. Bacterial biosynthesis of carotenoids was also associated with protection against EAC. Finally, the abundance of the periodontal pathogen <i>Porphyromonas gingivalis</i> trended with higher risk of ESCC. Overall, our findings have potential implications for the early detection and prevention of EAC and ESCC. <i>Cancer Res; 77(23); 6777-87. ©2017 AACR</i>.