Differences in intestinal flora between colorectal cancer patients and healthy people
Objective To analyze the fecal microbial communities of colorectal cancer(CC)patients vs healthy people,and the differences in microflora between CC tissues and adjacent tissues,hoping to find the correlation between intestinal microflora differences and CC.Methods Patients admitted to the hospital from September 2021 to October 2022 were se-lected.A total of 60 samples were collected,among which 11 stool samples were collected from colorectal tumor patients and recorded as group A.Twenty samples of CC tumor tissue and 20 samples of corresponding paracancer tissue were col-lected,which were respectively recorded as group B and group C.Meanwhile,9 fecal samples from healthy individuals were collected and recorded as group D.Microflora sequencing was performed to analyze the composition and diversity of microflora as well as the differences among group A and group D,group B and group C.Results A total of 4,335,646 high quality amplified sequences were obtained,which were merged according to 97％sequence similarity and compared with the Greengenes database for species annotation to generate the characteristic sequence OTUs and abundance data tables.The dilution curve of diversity tended to flatten out,indicating that the sequencing covered most species.At phylum level,dominant bacteria were roughly consistent in groups A,B,C and D,among which Firmicutes,Bacteroidetes and Pro-teobacteria accounted for more than 90％.No bacteria with different relative abundance were found between group A and group D,and between group B and group C.On the genus level,the relative abundance of Lachnobacterium in group D was significantly higher than that in group A(Z=-2.309,P=0.027),and that of Ruminococcus in group A was signific-antly higher than that in group D(Z=-2.309,P=0.027).Chaol index in group A was significantly lower than that in group D(Z=-3.001,P=0.003).Chaol index showed no statistical significance between group B and group C.For Shannon in-dex,there was no significant statistical difference between group A and D,and between group B and C.There was a signi-ficant structural difference in the beta diversity between groups A and D(F=2.684,P=0.004),but not in the beta diversity between groups B and C.As for the screening of bacterial flora differential species,there were 6 different species in CC group(group A)compared with group A and D,including g_Ruminococcus,f_Haliangiaceae,f_[Tissierellaceae],p_Fus-obacteria,o_Fusobacteriales and c_Fusobacteriia.In the healthy control group(group D),14 distinct species were identi-fied,including p_Firmicutes,o_Clostridiales,c_Clostridia,g_Lachnobacterium,f_Ruminococcaceae_g_Ruminococcus,g_Lachnospira,f_Christensenellaceae,o_Alteromonadales,c_Mollicutes,p_Tenericutes,o_RF39,c_Thermoleophilia,g_Paracoccus,f_Nocardiaceae.For tissue samples,no differential species was found between CC tissues and paracancer tissues after LEfSe analysis.Conclusion There are differences in the dominant species and relative abundance at phylum and genus levels,among which Clostridium may be involved in the occurrence of CC.The flora richness of CC patients de-creased significantly.Compared with healthy individuals,there was structural separation of flora community,and the relat-ive abundance of short-chain fatty acids producing bacteria in CC patients decreased significantly,while opportunistic pathogens increased,suggesting that there is a certain imbalance of flora in CC patients.There are no significant changes in the relative abundance and diversity of flora in CC tissue and adjacent tissues,and no obvious separation of flora structure,suggesting that there may be no difference in the flora between cancer and adjacent tissues.
万方数据
维普
