Saliva Metabolomics Study Of Patients With Oral Squamous Cell

Objective: In this study,metabolomics research methods were used to analyze the saliva samples from patients with oral squamous cell carcinoma and from healthy people as control.The aims of this study are to 1)determine the difference(significant or insignificant)of metabolites sourced from the two groups;and 2)preliminary discuss the possible metabolic pathways from different groups by using metabolomics analytical method.Methods:According to the saliva collection method,oral squamous cell were collected from the patients who received oral and maxillofacial surgery and oral mucosa from the Affiliated Hospital of Qingdao University and health volunteers with normal oral mucosa between December 2016 to June 2017.All saliva collectors have to be fulfilled the following crietias: 1)ruled out of systemic diseases and any other oral mucosal diseases;2)without any hormone drug or immunosuppressive drug within six months of the sampling date.46 saliva samples were collected and divided into two groups,of which 26 cases were typical clinical manifestationsdiagnosed as oral squamous cell carcinoma by pathology while the rest 20 cases were control(sourced from healthy people).Gas chromatography-time-of-flight mass spectrometry(GC-TOF-MS)was used to detect the saliva samples in random order.Multivariate pattern recognition analysis were accompolished using SIMCA software(V14.1,MKS Data Analytics Solutions,Umea,Sweden),principal component analysis(PCA),and Orthogonal Partial Least Squares-discriminant analysis(OPLS-DA).Metabolic markers mass spectrometry were identified by compared to the LECO-Fiehn Rtx5 database After comprehensive analysis of the pathways where differential metabolites are located(including enrichment analysis and topological analysis),it was further screened and the key pathways with the highest correlation with metabolic differences were determined.Each group was compared and the Euclidean distance matrix was used to calculate the quantitative value of differential metabolites.All different metabolites were hierarchically clustered using completely linked method to generate a thermodynamic map to demonstrate metabolism and,as a result,the corresponding amount of metabolites were expressed.Results:There was significant difference(p<0.05)in salivary metabolism profile between the OSCC patient group and the healthy control group detected by the GC-TOF-MS method.Six metabolites were finally identified through the LECO-Fiehn Rtx5 database,which wereuric acid;ribose;tyrosine;phytosphingosine;dihydrosphingosine;and p-hydroxylactate.The hierarchical clustering and tyrosine concentration were found higher from OSCC patients and the corresponding metabolic trend was up-regulated.On the other hand,the rest metabolite concentrations from OSCC patients was relative lower compared to control and the corresponding metabolic trendswere down-regulated.Results obtained from further investigation revealed that the un-regulated of amino acid metabolism,disturbance of energy metabolism and imbalance of lipid metabolism in patients with OSCC.The abnormality of the TCA cycle was also observed.Conclusion:Results obtained from this study proved that it is possible to using gas chromatography-time-of-flight mass spectrometry for determing the metabolites from saliva samples collected from OSCC patients and healthy people.Six differential metabolisms were identified.The qualitative analysis revealedpotential metabolic pathways in different metabolites between the two groups.