| Objective: Papillary thyroid carcinoma(PTC)is extremely common,accounting for about 85-90% of all thyroid tumors.Ultrasound-guided fine-needle aspiration biopsy(FNAB)is the most effective method to diagnose PTC,but it can not effectively distinguish benign from malignant at the cytological level,resulting in 10-25%diagnostic uncertainty.It is urgent to develop new preoperative methods,especially the use of biomarker methods for effective diagnosis of PTC.Some studies have shown that the collective activity of intestinal microbiota and the derived metabolites can strongly affect the protection and susceptibility to malignant tumors.However,the factors affecting the pathogenesis of PTC are complex.The existing research on intestinal microbiota and PTC has not clarified the involved mechanism,and there is insufficient clinical observation evidence.In addition,metabonomics research is also widely used in the field of thyroid diseases.Metabolomics can discover new biomarkers and reveal the importance of metabolomics for clinical diagnosis.Therefore,it is necessary to further develop the multi-group analysis of PTC.The purpose of this study is to analyze the differences in serum metabonomics of PTC,screen the differential metabolites and related metabolic pathways,and find out the key biomarkers firstly.Subsequently,a precise targeted metabonomic analysis and detection method suitable for key biomarkers was established to further clarify the key biomarkers for PTC diagnosis and provide a new PTC diagnosis method for clinical reference.Finally,exploring whether the intestinal microbiota structure of PTC patients is abnormal and evaluating the clinical relevance and diagnostic efficacy.Besides,the differential microbiota,differential intestinal microbiota metabolites and related metabolic pathways are analyzed,and the correlation analysis with the serum metabonomic structure is performed.It is expected to explore a new method and strategy that may affect the occurrence and development,diagnosis,early intervention and treatment of PTC.Methods: First of all,the serum samples of PTC patients were analyzed by non-targeted metabonomics in order to find differential metabolites and abnormal metabolic pathways,further to find key biomarkers from the metabonomics level,and provide a new exploration direction for clinical diagnosis and treatment observation of PTC.Secondly,the accurate quantitative analysis of key biomarkers will be carried out to provide a new diagnostic method for PTC for clinical reference through the establishment of targeted metabonomics detection method.Finally,the purpose of exploring the metabolic pathways involved in the differential microbiota and differential metabolites was realized.On this basis,this study aims to find susceptibility genes through combined metabonomic analysis,and then explore the possible pathogenesis,so as to provide a theoretical basis for the clinical research of PTC.Results: The PTC group screened 22 differential metabolites,which may become a potential biomarker for the discovery of PTC.The related differential metabolites are mainly involved in steroid hormone synthesis,histidine metabolism,tyrosine metabolism,amino acid biosynthesis,glutathione metabolism,amino sugar and nucleotide sugar metabolism and starch and sucrose metabolism.Through further analysis,it is found that nine amino acid differential metabolites may be used as key biomarkers for diagnosis of PTC,and amino acid metabolism may play an important role in the occurrence and development of PTC.The targeted metabolomic analysis method established in this study can be successfully used for the detection of nine amino acid metabolites.The method has high sensitivity,accuracy,precision and stability,and can be successfully used for the quantitative detection of PTC serum samples.In addition,it is proved that the nine amino acid metabolites can be used as diagnostic biomarkers for PTC,and the combined analysis of methionine and tryptophan as metabolites has better diagnostic efficacy through the investigation of diagnostic efficacy.There are differences in the structure of intestinal microbiota in PTC patients.The dominant microbiota are Firmicutes,Bacteroidetes,Proteobacteria and Actinobacteria.At the genus level,the increase of Bifidobacterium and Blautia in PTC group is the most obvious than that in HC group,while the decrease of Prevotella,Faecalibacterium,Sutterella and Collinsella is the most obvious.The analysis of significant differences found that Megamonas is the dominant marker of healthy people,Streptococcus,Streptococcaceae,Weissella,Leuconostocaceae,Shigella,S24-7,Lactobacillus,Lactobacillaceae,Enterobacteriales,Enterobacteriaceae and Gammaproteobacteria are the dominant marker of PTC patients,and may become the key biomarker of identifying HC and PTC.Streptococcus,Streptococcaceae,Shigella,Lactobacillus,Enterobacteriales and Enterobacteriaceae may be the key biomarker strains for the diagnosis of PTC,which have the best diagnostic efficacy as a combination of combined factors,and may be used as a new non-invasive detection method for clinical reference.The differential metabolisms of tryptophan,methionine,valine,histidine and threonine in serum are significantly correlated with the microbiota from Firmicutes and Proteobacteria.The dysbiosis of the two microbiota groups may be closely related to the occurrence and development of PTC and the metabolism of amino acids in PTC patients.Conclusions: Based on the analysis of non-targeted and targeted metabonomics,this study found that nine amino acid metabolites can be used as key biomarkers of PTC,and the combined analysis of methionine and tryptophan has higher diagnostic efficiency.It may be a new minimally invasive detection method with clinical application value.Streptococcus,Streptococcaceae,Shigella,Lactobacillus,Enterobacteriales and Enterobacteriaceae may be the key biomarker strains for the diagnosis of PTC,which have the best diagnostic efficacy as a combination of combined factors,and may be used as a new non-invasive detection method for clinical reference.The dysbacteriosis of intestinal microbiota in PTC patients leads to the disorder of amino acid metabolism in vivo,and then triggers inflammatory reaction and regulates the immunosuppressive tumor microenvironment. |
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