Metagenomic Studies Of The Oral Microbiomes In Laryngeal Squamous Cell Carcinoma Patients

Background Laryngeal carcinoma is one of the malignant tumors in head and neck cancer,most of which are classified as squamous cell cancer by histopathology.Currently known risk factors of laryngeal carcinoma include smoking,alcohol and infection,but the risk factors of laryngeal carcinoma are not fully understood.Due to the special structure of laryngeal carcinoma,the early symptoms of laryngeal carcinoma are not specific and difficult be detected,which is ignored by many patients.At the same time,laryngeal carcinoma is prone to distant metastasis,and patients are diagnosed at an advanced stage.and the survival rate is not improved after clinical comprehensive treatment.Therefore,early detection and treatment of laryngeal carcinoma is important,and it is necessary to explore the related pathogenic factors and pathogenesis of laryngeal carcinoma.Oral microbiota have been found to be closely related to the occurrence of the head and neck squamous cell carcinoma.The relationship between oral microbiota and laryngeal carcinoma was explored.Objective In this study,the composition and functional characteristics of oral buccal mucosa microbiota in laryngeal carcinoma patients were analyzed using metagenomic high-throughput sequencing,and the correlation between oral microbiota and laryngeal carcinoma was further explored.Methods The study included 14 laryngeal squamous cell carcinoma patients and 8 healthy control subjects who met the criteria.The clinical characteristics of the subjects were collected,and swab samples of the oral and buccal mucosa were collected.DNA was extracted for metagenomic sequencing and bioinformatics analysis to analyze the microbiota composition and functional characteristics of the oral buccal mucosa.Results 1.In LSCC group and healthy control group,a total of 86 phyla,135 classes,241 orders,454 families,1402 genera and 6170 species were obtained.At the phylum level,The dominant phyla in two groups were Firmicutes,Proteobacteria,Actinobacteria,Bacteroidetes,Fusobacteria,Candidatus_Saccharibacteria and Spirochaetes.At the geuns level,The dominant genera in two groups were Streptococcus,Actinomyces,Neisseria,Prevotella,Pseudomonas and Rohia_fMicrococcaceae.At the species level,the dominant species in two groups were Streptococcus_mitis,unclassified_gStreptococcus,Actinomyces_oris,Streptococcus_Pneumoniae,unclassified_gPseudomonas,unclassified_gNeisseria,Lautropia_mirabilis,Porphyromonas_gingivalis and Streptococcus_oralis.2.Analysis of the differences between the two groups showed that at phylum level,the relative abundance of Candidatus_Saccharibacteria decreased in LSCC group.At the genus level,the relative abundance of unclassified_f<sub>Mycoplasmataceae was increased in LSCC group,while the relative abundance of Rothia_f<sub>Micrococcaceae,Pseudomonas,Salmonella,Klebsiella,Acinetobacter,Leeuwenhoekiella,Shigella and Flavonifractor was significantly decreased in LSCC group.At the species level,the relative abundance of Actinomyces_sp._oral_taxon₄48 and Neisseria_cinerea increased in LSCC group,while the relative abundance of Rothia_dentocariosa,Pseudomonas（Pseudomonas_fluorescens and Pseudomonas_aeruginosa）was significantly decreased in LSCC group.The relative abundance of Porphyromonas_gingivalis and Fusobacterium_nucleatum were decreased in LSCC group.The density of oral microbiota network in the LSCC group was significantly higher than that in the healthy control group,possibly because the occurrence of tumor increased the complexity of oral microbiota community.3.Based on the functional annotation of KEGG and CAZymes database,the functional characteristics of oral microbiota in the two groups were as follows: In KEGG Level 1 function,Metabolism was the most abundant,followed by genetic information processing and environmental information processing.KEGG Level 2 function,global and overview maps,carbohydrate metabolism,amino acid metabolism,membrane transport,translation,replication and repair,metabolism of cofactors and vitamins.Glycosyl transferases,glycoside hydrolases and carbohydrate esterases were the main carbohydrate active enzymes.Analysis of functional differences between the two groups showed that the abundance of functional genes for biosynthesis of aminoacids,cysteine and methionine metabolism,pentose phosphate pathway,methane metabolism and glycosyl Transferase increased in LSCC group.4.In the analysis of the correlation between different microbiota and different functions,the unclassified_gPseudomonas,Pseudomonas_fluorescens,Rothia_dentocariosa and Actinomyces_sp._oral_taxon₄48 were closely related to biosynthesis of aminoacids,cysteine and methionine metabolism,pentose phosphate pathway,methane metabolism,glycosyl transferases function.Conlusions1.The dominant flora in oral buccal mucosa of LSCC patients is similar to that in oral saliva.2.There are significant differences in the composition and function of oral buccal mucosa microbiota between healthy subjects and LSCC patients.3.Actinomyces_sp._oral_taxon₄48,Neisseria_cinerea,Klebsiella,Shigella,Pseudomonas（Pseudomonas_fluorescens and Pseudomonas_aeruginos ect）,Rothia_Dentocariosa,Salmonella_enterica,Porphyromonas_gingivalis and Fusobacterium_nucleatum may be associated with LSCC.4.Biosynthesis of aminoacids,cysteine and methionine metabolism,methane metabolism,pentose phosphate pathway and glycosyltransferase synthesis may be related to the occurrence and development of LSCC.