The EACR’s Top 10 Cancer Research Publications is a regular summary of the most interesting and impactful recent papers in cancer research. It is curated by the Board of the European Association for Cancer Research (EACR).
The list below appears in no particular order, and the summary information has been provided by the authors.
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S. Tomkovich et al., Journal of Clinical Investigation 2019;129(4):1699–1712
Summary of the findings
Mucosal-associated polymicrobial biofilms were previously identified in ~50% of colorectal cancer (CRC) patients and ~13% of healthy patients, however whether this microbial organization contributed to carcinogenesis was unclear. We administered biofilm-associated microbes obtained from CRC or healthy patients undergoing screening colonoscopy to three Wnt-based CRC mouse models (germ-free ApcMinΔ850/+;Il10–/– or ApcMinΔ850/+ and specific pathogen–free ApcMinΔ716/+ mice) to test their functional role in CRC. In contrast to bacteria derived from biofilm-negative colon mucosa of healthy patients, mucosal bacterial biofilm communities from either CRC or healthy patients promoted tumorigenesis in genetically-susceptible mice. Furthermore, human mucosa biofilm communities induced biofilm formation in the mouse colon and the mucosal-associated tumorigenic biofilm communities were transmissible and promoted CRC when administered to a new cohort of germ-free ApcMinΔ850/+;Il10–/– mice. Our findings suggest that, at least some, human colon mucosal biofilms are carcinogenic in CRC mouse models, implicating both microbiota organization and composition as drivers of CRC.
Future impacts of the findings
These findings highlight the importance of evaluating the organization and location of microbial communities within the host in addition to determining microbiota composition. Beyond examining microbiota community composition and organization in the context of CRC, there is a need to determine how these communities interact with the host at a functional level. A deeper understanding of temporal biofilm formation and associated functions will be critical for CRC prevention and treatment. An essential next step will be conducting prospective longitudinal studies in human populations to characterize biofilm assembly and to determine key biofilm microbial members that predict individual CRC risk.
Figure Caption: Bacteria derived from human colon mucosal biofilms identified on mucosal biopsies from healthy patients and tumor or paired normal tissue resected from CRC patients promoted tumorigenesis in CRC mouse models. In mice, biofilm communities expressed genes associated with bacterial secretion systems, sporulation, peptidoglycan synthesis and cytoskeletal proteins.
