The gut microbiota composition in patients with right- and left-sided colorectal cancer and after curative colectomy, as analyzed by 16S rRNA gene amplicon sequencing

Abstract

Background Gut pathological microbial imbalance or dysbiosis is closely associated with colorectal cancer. Although there are observable differences in molecular and clinical characteristics between patients with right- and left-sided colon cancer, differences in their gut microbiomes have not been thoroughly investigated. Furthermore, subsequent changes in microbiota status after partial colectomy remain unknown. We examined the human gut microbiota composition to determine its relationship with colon cancer and partial colon resection according to location. Methods Stool samples from forty-one subjects (10 in the control group, 10 in the right-sided colon cancer [RCC] group, 6 in the sigmoid colon cancer [SCC] group, 9 in the right colon resection [RCR] group and 6 in the sigmoid colon resection [SCR] group) were collected, and DNA was extracted. After terminal restriction fragment length polymorphism (T-RFLP) analysis, the samples were subjected to 16S rRNA gene amplicon sequencing, and the metabolic function of the microbiota was predicted using PICRUSt2. Results T-RFLP analysis showed a reduced ratio of clostridial cluster XIVa in the SCC patients and clostridial cluster IX in the RCC patients, although these changes were not evident in the RCR or SCR patients. 16S rRNA gene amplicon sequencing demonstrated that the diversity of the gut microbiota in the RCC group was higher than that in the control group, and the diversity in the SCR group was significantly higher than that in the RCR group. Principal coordinate analysis (PCoA) revealed significant differences according to the group. Analyses of the microbiota revealed that Firmicutes was significantly dominant in the RCC group and that the SCC group had a higher abundance of Verrucomicrobia. At the genus level, linear discriminant analysis effect size (LEfSe) revealed several bacteria, such as Ruminococcaceae, Streptococcaceae, Clostridiaceae, Gemellaceae, and Desulfovibrio, in the RCC group and several oral microbiomes in the SCC group. Metabolic function prediction revealed that cholesterol transport- and metabolism-related enzymes were specifically upregulated in the RCC group and that cobalamin metabolism-related enzymes were downregulated in the SCC group. Conclusion Gut microbial properties differ between RCC and SCC patients and between right hemicolectomy and sigmoidectomy patients and may contribute to clinical manifestations.

Identification of taxonomic changes in the fecal bacteriome associated with colorectal polyps and cancer: potential biomarkers for early diagnosis

“…Our study revealed heterogeneity in the bacteriome of CRC patients, specially related to the diversity and taxonomic composition. Although factors such as the location and stage of CRC are known to potentially influence the variability of the microbiomes ( Sheng et al, 2019 ; Suga et al, 2022 ), we did not observe associations in our study population, which may be due to the limited number of patients. Regarding the stage of CRC, the genus Pediococcus was significantly reduced in advanced cases ( Figure 8D ), and showed a negative co-occurrence with Desulfovibrio , suggesting a potential protective role against CRC progression ( Figure 6 ).…”

An approach to finding specific forms of dysbiosis that associate with different disorders

“…[1,[26][27][28]); and (b) our ANHAC group showed dysbiosis, overall. Consistent with (b), the random forest could not differentiate the ANHAC group from a grouping of cancer diagnoses (see Supplementary Information and compare [1,[29][30][31][32]). However, the absence of healthy controls limits characterization of our ANHAC group and the nature of its dysbiosis.…”

The impact of a modified microbiota-accessible carbohydrate diet on gut microbiome and clinical symptoms in colorectal cancer patients following surgical resection

“…We found that beta-diversity was significantly different, with distinct microbial profiles emerging after surgical resection of right-sided CRC compared to left-sided CRC. A previous study reported lower levels of Gemellaceae in patients who underwent right CRC resection, while the Firmicutes phylum was found to be abundant in those who underwent sigmoid colon cancer resection ( Suga et al, 2022 ). Taken together, our results underscore the difference in microbiome composition based on the location of resection.…”