The gut microbiota in conventional and serrated precursors of colorectal cancerOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study examined how the gut microbiota relates to the two major precursor lesions of colorectal cancer: conventional adenomas and serrated polyps. Colorectal cancer is a heterogeneous disease, and the authors tested for the first time whether the gut microbiota's relationship to colorectal cancer differs by the specific type of precursor polyp. Gut microbiota were assessed using 16S rRNA gene sequencing of stool samples, allowing comparison of diversity, overall composition, and taxon abundance across groups.
Who was studied?
The study included 540 adults who underwent colonoscopy screening. Participants were categorized as conventional adenoma cases (n = 144), serrated polyp cases (n = 73), or polyp-free controls (n = 323). Conventional adenoma cases were further divided by location (proximal, n = 87; distal, n = 55) and stage (non-advanced, n = 121; advanced, n = 22), and serrated polyp cases were subdivided into hyperplastic polyp (n = 40) and sessile serrated adenoma (n = 33).
What were the most important findings?
Conventional adenoma cases had lower gut microbial species richness in stool than polyp-free controls, and this association was strongest among advanced conventional adenoma cases. In terms of overall microbiota composition, differences from controls were seen specifically among distal or advanced conventional adenoma cases. These patterns indicate that the gut microbiota relationship to colorectal cancer precursors is not uniform but varies by polyp type, location, and severity.
What are the greatest implications of this study?
By distinguishing microbiota associations between conventional adenomas and serrated polyps, this study suggests that colorectal cancer's different developmental pathways may have distinct microbial signatures. The stronger association with advanced and distal conventional adenomas points to species richness and composition as potentially useful features for identifying higher-risk precursor lesions. These findings support future research treating colorectal cancer precursors as biologically distinct subtypes rather than a single category when studying the gut microbiota.