| Background: Gastric cancer is the most common malignant tumor in China.Since early GC onsets with morbidity concealment and barely no specific clinical symptoms,most GC patients had reached the advanced stage at the time of seeking medical advices.Hence,early diagnosis is the key to improve the prognosis.With the development of next-generation sequencing technology and mass spectrometry technology,more and more attention has been paid to the multi-omics analysis.Many studies had been used metabolomics and transcriptomics to explore the pathogenesis of tumor.Saliva is an important peripheral body fluid,which can be used to monitor the physiological and pathological changes of human body,and it has great advantages in collection,storage,transportation and large-scale sampling.In this study,salivary metabolites profiling had been performed to find biomarkers and Illumina sequencing had been performed to search simultaneous transcriptomic evidence.Methods: Saliva of 157 patients with gastric cancer and 30 patients with gastritis were performed by untargeted UHPLC-QTOF-MS.Then the student' t-test(P < 0.05)and OPLS-DA(VIP > 1)analysis were performed to find the diagnostic biomarkers.After that,the patients were followed up and the Cox risk regression analysis was used to screen out the prognosis biomarkers.At the same time,100 samples of gastric cancer and 30 samples of paracancerous tissues were collected for transcriptome sequencing.The absolute value of Q(p-value corrected by multiple hypothesis test)was less than 0.05,and the absolute value of fold change between the two groups was more than 2 as the standard to screen significant deg.Finally,the data of the two groups were enriched and analyzed by KEGG pathway,and the correlation analysis was carried out on the platform of KEGG database.Results: 58 different metabolites were obtained in saliva by UHPLC-MS.The diagnostic model based on 8 Differential metabolites provided the best diagnostic sensitivity and specificity,which were 90.5% and 73.3% respectively after one method cross validation analysis.Further Cox regression analysis showed that there was a significant correlation between 5-methyl-thf and prognosis.Through the correlation analysis of metabolomics and transcriptome,we found that most of the differential metabolites were highly consistent with the corresponding regulatory genes.Conclusion: In conclusion,salivary metabolites can be used as an appropriate vector for the diagnosis and prognosis of gastric cancer,and it can accurately reflect the changes of gastric cancer genome. |
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