Study On The Difference Of Gut Microbiota Structure Between Colorectal Cancer Patients And Healthy People In Mongolia

Objective: The purpose of this study was to understand the gut microbiota structure of Mongolian population,and to compare the structural differences of gut microbiota between Mongolian healthy population and Mongolian colorectal cancer patients.It is expected to find the marker microbiota of Mongolian colorectal cancer patients and explore the relationship between the gut microbial community structure of Mongolian and the occurrence and development of colorectal cancer.Methods: According to the criteria set in advance,a total of 31 Mongolian patients treated in Inner Mongolia Cancer Hospital and International Mongolian Hospital of Inner Mongolia from March 2019 to Jun 2021 were selected as the research subjects.Mongolian patients with colorectal cancer were included in the experimental group,and Mongolian healthy people were included in the control group.Fresh stool samples of the study subjects were collected,and all stool samples were sequenced by 16 S r RNA sequencing technology.The preliminary obtained sequences were processed by DADA2 to obtain high-quality sequences.Then taxonomic annotation and phylogenetic tree construction were carried out and visualized on QIIME2 platform.After species composition analysis,Alpha diversity analysis and Beta diversity analysis,LEf Se analysis and random forest analysis were used to identify the main marker microbiota in the experimental group and the control group.Results: There was no significant difference in within habitat diversity between the experimental group and the control group(P > 0.05),that is,there was no significant difference in richness,diversity and evenness between the experimental group and the control group.However,in terms of species composition,there are significant differences in the composition of gut microbiota between the experimental group and the control group at the level of phylum,class,order,family,genus and species.At the phylum level,cyanobacteria and lentisphaerae in the control group were significantly enriched,while fusobacteria in the experimental group were significantly enriched.At the genus level,the control group was enriched in Faecalibacterium,Micrococcus,Dialister,Slackia,Butyrivibrio,Ruminococcus,Sutterella,Victivallis,Lachnobacterium,Catenibacterium,Butyricicoccus and Megasphaera.The experimental group was enriched in Porphyromonas,Shigella,Streptococcus,Clostridium,Allobaculum,Peptostreptococcus,campylobacter,Eggerthella,Fusobacterium,Lactobacillus,Turicibacter,collinsella,Filifactor and Parvimonas.Through random forest map analysis,it was found that Ruminococcus,Lachnobacterium,Dialister,Megasphaera,Sutterella,Butyrivibrio,Catenibacterium,Faecalibacterium,Oscillospira,Phascolarctobacterium,Prevotella,Peptostreptococcus,Streptococcus,Shigella,Turicibacter,SMB53,Collinsella,Lactobacillus and Lachnospira were the marker species affecting the grouping of the control group and the experimental group.Conclusion: 1.There are differences in gut microbiota between Mongolian healthy people and Mongolian patients with colorectal cancer at the level of phylum,class,order,family,genus and species;2.Porphyromonas,Shigella,Peptostreptococcus and Fusobacterium can be regarded as biomarkers of Mongolian colorectal cancer;3.The increase in the abundance of Shigella,Streptococcus and Peptostreptococcus,and the decrease in the abundance of Ruminococcus,dialist,butyrivibrio and sutterella may promote the occurrence and development of Mongolian colorectal cancer,which can be used for further study on the microbiota related to prevention and treatment.