December 13, 2021

Oral microbes and gastric cancer

Studies in three large population cohorts that include Asian, African American and European American people support a role for the oral microbiota — the collection of microbial species in the mouth — in gastric cancer development.

The oral microbiota — the collection of microbial species in the mouth — has been associated with gastric cancer risk, but previous studies have been limited by the design and methodology for characterizing microbes. 

Xiao-Ou Shu, MD, PhD, and colleagues have now explored the relationship between the oral microbiota and gastric cancer risk in a prospective case-control study in three populations (Shanghai Women’s Health Study, Shanghai Men’s Health Study, Southern Community Cohort Study). They used shotgun metagenomic sequencing to comprehensively characterize all organisms present in buccal (cheek) samples collected at enrollment from 165 people later diagnosed with gastric cancer and 323 matched controls. 

The researchers found that decreased overall microbial diversity, altered abundance of several taxa, and multiple microbial functional markers were associated with gastric cancer risk. The top two gene families and pathways associated with decreased risk are involved in hexitol metabolism. 

The findings, reported in the International Journal of Cancer, support a role for the oral microbiota in gastric cancer development.

This research was supported by the National Cancer Institute (CA204113), the Advanced Computing Center for Research and Education at Vanderbilt University, and the Survey and Biospecimen Shared Resource, supported in part by the Vanderbilt-Ingram Cancer Center (CA068485). The parent population cohort studies also were supported by the NCI (CA173640, CA182910, CA202979).