The Effect Of Smoking On Intestinal Microflora And Occurrence Of Colorectal Neoplasms

Research purposes: In recent years,the incidence of colorectal cancer has been increasing steadily in China.At present,Asia Pacific Consensus has listed smoking as one of the risk factors for colorectal cancer,and appeals to smokers to enhance the screening.Meanwhile,other literature has pointed OTU that smoking cessation in normal population can change the composition of intestinal microflora.In normal population and inflammatory bowel disease patients,the intestinal microflora between smokers and nonsmokers is different.But the effects of smoking on intestinal microflora are not clear in colorectal adenoma or in colorectal cancer patients today.In summary,our research intends to make a further study on the relationship between smoking,intestinal microflora and colorectal cancer.Methods: We collected the fecal samples and the clinical informations of those who would undergo a colonoscopy or a surgical operation in ××Hospital from July 2016 to June 2017,including 20 cases of healthy control,20 cases of colorectal adenoma and 14 cases of colorectal adenocarcinoma.The proportion of smokers and nonsmokers in each group is 1:1.We extracted fecal genomic DNA,then carried OTU Illumina Miseq high-throughput sequencing and biological information analysis,to find OTU whether there are differences in intestinal microflora between each group.Results: 1.Compared with healthy control group and colorectal adenoma group,the richness and diversity of intestinal microflora is significantly increased in colorectal adenocarcinoma group.But there is no difference in abundance or diversity of intestinal microflora between smoking group and nonsmoking group.2.Between normal healthy control group and colorectal adenocarcinoma group,the abundances of intestinal microflora are significantly changed from phylum to genus level.Meanwhile in each level,there are also significant differences of the intestinal microflora abundance between smoking group and nonsmoking group.Linear discriminant analysis(LDA)effect size(LEfSe)method revealed an increased abundance of Porphyromonadaceae in CRC group and is an increased abundance of Lachnospira in HC group,which contribute greatly to the division of two groups.In the smoking group,the abundance of Megamonas and Fusobacteria with its following class,order,family and genera is significantly higher,and a decrease of the abundance can be observed in Moraxellaceae with Acinetobacter included and Synergistetes with its following class,order and family.3.The abundance of Fusobacterium is significantly increased in both colorectal adenocarcinoma group and smoking group.Conclusion: Compared with normal healthy people,there is a difference in the composition of intestinal microflora in patients with colorectal cancer.And smoking can also change the composition of intestinal microflora.The role of intestinal microflora in occurrenc and development of colorectal cancer promoted by smoking needs further study.