The gut microbiota composition in patients with right- and left-sided colorectal cancer and after curative colectomy, as analyzed by 16S rRNA gene amplicon sequencingOriginal 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 the composition of the gut microbiota in patients with colorectal cancer, comparing right-sided (RCC) and sigmoid, left-sided (SCC) tumor locations. It also assessed how microbiota composition changes after partial colectomy performed to remove these tumors. Stool samples were analyzed using terminal restriction fragment length polymorphism (T-RFLP) and 16S rRNA gene amplicon sequencing, with PICRUSt2 used to predict the metabolic function of the microbial community.
Who was studied?
Forty-one subjects provided stool samples across five groups: 10 healthy controls, 10 patients with right-sided colon cancer (RCC), 6 patients with sigmoid colon cancer (SCC), 9 patients after right colon resection (RCR), and 6 patients after sigmoid colon resection (SCR). This design allowed comparison of microbiota both by tumor location and by surgical status.
What were the most important findings?
T-RFLP analysis showed a reduced ratio of clostridial cluster XIVa in patients with sigmoid colon cancer and a reduced ratio of clostridial cluster IX in patients with right-sided colon cancer. These reductions were not evident in the corresponding post-colectomy groups (RCR or SCR), suggesting a difference between the pre-resection cancer state and the post-resection state. The abstract text was truncated before the 16S rRNA sequencing results and PICRUSt2 functional predictions were fully described.
What are the greatest implications of this study?
The findings suggest that right-sided and left-sided (sigmoid) colorectal cancers are associated with distinct patterns of gut microbial dysbiosis, specifically involving different clostridial clusters. Because these dysbiosis patterns were not observed after curative colectomy, tumor location-specific microbiota alterations may be tied to the presence of the tumor itself rather than persisting as a fixed feature of the gut environment. This supports the idea that gut microbiota assessment could be a useful, location-aware tool in understanding colorectal cancer biology.