The Composition Of Oral Microbiota Between Gingival Squamous Cell Carcinoma And Periodontitis:Generality And Discrepancy

Objectives: Previous studies have proved that periodontitis may be an independent risk factor of oral squamous cell carcinoma(OSCC)epidemiologically.Along with the important role of microbiota in the cancer process and the specific anatomical position,our study explored the microbial composition and functions in periodontitis and gingival squamous cell carcinoma(GSCC)to seek the relationship.Materials and Methods: According to the inclusive and exclusive criterions,we recruited GSCC patients(n=10),matched periodontitis patients(n=15),and healthy individuals(n=15)from 2017-2019 in China Medical University.After obtaining ethical approval from the ethics committee and informed consent from the patients,we recorded the demographic information and clinical periodontal conditions from the subjects.Saliva and subgingival plaque samples from three groups were collected according to the protocols of human microbiome project(HMP).Tongue dorsum,buccal mucosa,cancerous tissue,and paracancerous tissue samples were additionally collected from GSCC group.After DNA extraction,16 S rDNA amplicon sequencing and functional prediction were applied for the taxonomic analysis.The data was filtered by quality and clustered into operational taxonomy unites(OTU).Then species composition analysis,diversity analysis,comparison among groups,and differentiate species analysis were applied.The bar graph,box plot,linear discriminant analysis(LDA)was used for visualized analysis on SPSS 24.0 and Graphpad Prism 8.0.Results: 1.Following sequence assembly and filtering low quality and short sequence reads,5,687,082 clean reads were obtained with an average length of 424 bp per sequence conformed to analysis requirement.1473 OTUs were assigned and classified to 18 phylum and 220 genera.2.Periodontal pathogens occupied 46% in GSCC.3.PCoA exhibited similar cluster between tongue dorsum and saliva in GSCC.4.Fusobacterium,Peptostreptococcus,and Prevotella were more abundant in cancerous tissues,while Streptococcus,Nesseria,and Haemophilus were more enriched in saliva or soft mucosa.5.GSCC showed lower richness than periodontitis.6.OTU generated from the subgingival plaque occupied 38.36% and 44.13% from saliva.In saliva and subgingival plaque,Atopobium was more prevalent in GSCC than periodontitis and controls in descending order.Lipopolysaccharide(LPS)biosynthesis increased in subgingival plaque of GSCC compared with the other two groups.The receiver operating characteristic(ROC)curve was applied to evaluate the reliability of biomarkers for GSCC.The area under the ROC curve(AUC)was 0.790 in the diagnostic model with 90%,66.70% of sensitivity and specificity,respectively,95% confidence interval(CI): 0.628-0.952.Conclusion: 1.Periodontal pathogens were abundant in GSCC.2.The microbial composition of tongue dorsum resembles the saliva in GSCC.3.Cancerous tissues harbor more periodontal pathogens than saliva or soft mucosa.4.A high level of Atopobium and LPS biosynthesis in subgingival plaque have the potential for increasing the risk of suffering from GSCC in individuals with periodontitis,which needs more evidence to clarify it.