The local tumor microbiome is associated with survival in late-stage colorectal cancer patients

This is the authors' abstract. We don't add key points for this paper.

Objective Colorectal cancer survival has been linked to the microbiome. Single organism analyses suggest Fusobacterium nucleatum as a marker of poor prognosis. However, in situ imaging of tumors demonstrate a polymicrobial tumor-associated community. To understand the role of these polymicrobial communities in survival, we performed an untargeted study of the microbiome in late-stage colorectal cancer patients. Design We conducted a nested case-control study in late-stage cancer patients undergoing resection for primary adenocarcinoma. The microbiome of paired colorectal tumor and adjacent tissue samples was profiled using 16S rRNA sequencing; we used compositionally aware ordination and differential ranking to profile the microbial community. Results We found a consistent difference in the microbiome between paired tumor and adjacent tissue, despite strong individual microbial identities. Tumors had higher relative abundance of genus Fusobacteria and Campylobacter at the expense of members of families Lachnospriaceae and Rumminococeae. Furthermore, a larger difference between normal and tumor tissue was associated with prognosis: patients with shorter survival had a larger difference between normal and tumor tissue. We found the difference was specifically related to taxa previously associated with cancer. Within the tumor tissue, we identified a 39 member community statistic associated with survival; for every log2 fold increase in this value, an individual’s odds of survival increased by 20% (OR survival 1.20; 95% CI 1.04, 1.33). Conclusion Our results suggest that a polymicrobial tumor-specific microbiome is associated with survival in late-stage colorectal cancer patients.