Gut mucus layer degradation is associated with aggressive cervical cancer phenotype

Background Gut microbiome community composition differs between cervical cancer (CC) patients and healthy controls, and increased gut diversity is associated with improved outcomes after treatment. We proposed that functions of specific microbial species adjoining the mucus layer may directly impact the biology of CC. Results In this study, we examined metagenomes of rectal swabs in 41 CC patients using whole-genome shotgun sequencing and found a significant association between molecular functions encoded by the metagenomes with markers of aggressive cancer including initial tumor size and stage. Profiling of the molecular function abundances and their distributions identified 2 microbial communities co-existing in each metagenome but with distinct metabolism and taxonomic structures. Community A (Clostridia and Proteobacteria predominant) was characterized by high activity of pathways involved in stress response, mucus glycan degradation and utilization of degradation byproducts. This community was prevalent in larger, advanced stage tumors. Conversely, community B (Bacteroidia predominant) was characterized by fast growth, active oxidative phosphorylation, and production of vitamins. This community was prevalent in small, early-stage tumors. Conclusions Based on these results, we propose that increased mucus layer degradation is associated with a more aggressive cervical cancer phenotype.