Plasma Metabolomic Study Of Gallbladder Carcinoma Based On Liquid Chromatography-Mass Spectrometry

Background:Gallbladder carcinoma(GBC)is a common malignancy of the biliary tract.Gallbladder carcinoma patients often have an insidious onset and lack typical clinical manifestations at an early stage and with a poor prognosis.In recent years,there have been more and more relevant studies on gallbladder carcinoma,but the specific biomarkers still need to be further discovered.Identifying biomarkers which are closely related to the gallbladder carcinoma will facilitate the early diagnosis and precise treatment of gallbladder carcinoma.Metabolomics is an emerging omics technology that is mainly used to study small molecular substances present in biological samples.The research objects include,tissues and various body fluids.In recent years,metabolomics has been widely used in the establishment of malignancy diagnosis models and the exploration of its occurrence mechanism.However,few studies on gallbladder cancer metabolomics have been reported so far.Objective:The goal of this study is to investigate the metabolic characteristics of plasma in gallbladder carcinoma?benign gallbladder disease and healthy control and establish an appropriate metabolite diagnosis model for early diagnosis of gallbladder carcinomaMaterials and methods:We collect plasma and clinical data of 44 cases of gallbladder cancer,94 cases of benign gallbladder disease and 60 cases of healthy persons who were diagnosed in the First Affiliated Hospital of Zhengzhou University from January 2018 to September 2019,and apply liquid chromatography-mass spectrometry(LC-MS)method to detect small molecule metabolites in plasma.Principal component analysis(PCA)and orthogonal partial least squares discriminant analysis(OPLS-DA)were performed on the detection results,combined with the Human Metabolome Database(HDMB)to identify differential metabolites,and enriched metabolic pathway analysis to find the key metabolic pathway.Then the differential metabolites were used to establish diagnosis models,and further screen out plasma biomarkers that can be used for the diagnosis of gallbladder carcinoma.In addition,the diagnostic performance of carcinoembryonic antigen(CEA),carbohydrate antigen 19-9(CA19-9)and diagnosis model which established in gallbladder carcinoma vs benign gallbladder disease was compared for the diagnosis of gallbladder carcinoma.Results:There are 33 differential metabolites including fatty acids,amino acids,phospholipids,carnitine,and bile acids which were identified in healthy people vs gallbladder cancer group,healthy people vs benign gallbladder disease group and benign gallbladder disease vs gallbladder cancer group.We found that 33 differential metabolites were clearly stratified among these three groups of people from hierarchical cluster analysis.There were 19,3 and 11 metabolites that showed high peak intensity in gallbladder cancer group,benign gallbladder disease group and healthy people group respectively.Enrichment analysis of metabolic pathways showed that differential metabolites were related to the metabolism of a-linolenic acid and linoleic acid,mitochondrial ?-oxidation of short-chain saturated fatty acids,phenylalanine and tyrosine metabolism,phospholipid biosynthesis,etc.In addition,this study used differential metabolites to establish disease diagnosis models in the training set.In the healthy person vs gallbladder cancer group,the diagnosis model combining phenylalanyltryptophan and a-linolenic acid can well distinguish the two types of disease.The area under the receiver operating characteristic(ROC)curve(AUC)was 0.945(0.89,1.00)(P<0.001)with the sensitivity and specificity which were 96.4%and 82.5%respectively.In the healthy people vs benign gallbladder disease group,the combination of Phenylalanyltryptophan,oleamide,LPE(20:4)and glycodeoxycholic acid was used to be a diagnostic model that can distinguish between healthy people and benign gallbladder disease,with an AUC of 0.90,a sensitivity of 86.9%and a specificity of 80.0%.In the benign gallbladder disease vs gallbladder cancer group,there was only indoleacrylic acid that was used as the diagnostic model,with an AUC of 0.90,a sensitivity of 85.7%and a specificity of 91.8%.At the same time,the diagnostic performance of established diagnostic models(indoleacrylic acid),CEA,and CA19-9 in benign gallbladder disease vs gallbladder cancer group was compared.There was an higher AUC in diagnostic model than CEA and CA19-9(0.69 and 0.73),the sensitivity was much higher than CEA(33.3%)and CA19-9(44.4%),while the specificity was slightly lower than the two(100%and 98.4%).Finally,the diagnostic performance of each diagnostic model and CEA,CA19-9 was verified in the verification set and the results were same as that is in the training set.Overall,the diagnostic performance of indoleacrylic acid was better than CEA and CA19-9.Conclusions:In this study,the metabolomic method of LC-MS was used to identify the differential metabolites in benign gallbladder diseases,gallbladder carcinoma and healthy people.At the same time,the diagnostic models for gallbladder carcinoma were established successfully,which provided new ideas for the early diagnosis of gallbladder carcinoma.