Figure 5

Graphical summary of the results. (A) Distinct taxonomic structure of the intratumoral microbiome in ACC patients with high and low species richness and association with survival. A rich microbial community in normal tissue is linked to an oral-type intratumoral community dominated by oral species with significantly increased abundances of Bacteroidota and decreased abundances of Actinobacteroidota. A microbial community with low richness is linked to the gut type intratumoral community populated by many species involved in mucus layer degradation. (B) Hypothetical model linking ACC development and progression to distinct changes in the taxonomic composition of the intratumoral microbiome and feedback effects. Sustained damage to salivary epithelia during the course of ACC development leads to the release of salivary glycans and the outgrowth of glycan-degrading bacterial taxa. In the low-richness intratumoral microbiome, which is not resilient, the outgrowing taxa are represented by non-oral gut-associated bacteria and Proteobacteria that promote tumor progression. In the high-richness intratumoral microbiome, which is more resilient, the taxa are represented by oral Bacteroidota. Although most other oral species are decreased, colonization by gut-associated glycan degraders is suppressed by oral microbes.