Metabolomic phenotype of gastric cancer and precancerous stages based on gas chromatography time-of-flight mass spectrometry
Background and Aim: To study the low-molecular-weight metabolites in blood plasma of patients with the progressive disease, gastric cancer, and to characterize different stages from chronic superficial gastritis (CSG) to chronic atrophic gastritis (CAG), intestinal metaplasia (IM), gastric dysplasia (DYS) and finally gastric cancer (GC). Methods: We applied gas chromatography time-of-flight mass spectrometry (GC/TOF-MS) to determine metabolites levels in plasma obtained from 80 patients including 19 with CSG, 13 with CAG, 10 with IM, 15 with DYS and 22 with GC (nine preoperation and 13 postoperation). Principal component analysis (PCA) and statistics were used to differentiate the stages and to identify the markers of gastric cancer. Results: Totally, 223 peaks were detected in GC/TOF-MS and 72 compounds were authentically identified. CSG showed distinct difference from the other groups of CAG, IM, DYS and GC, whose plots clustered closely. IM clustered closely to GC, suggesting similar metabolic patterns of them. Fifteen identified metabolites contributed most to the differentiating between CSG and GC, and characterized different stages of GC. Statistics revealed elevated levels of 2-Hydroxybutyrate, pyroglutamate, glutamate, asparagine, azelaic acid, ornithine, urate, 11-eicosenoic acid, 1-monohexadecanoylglycerol and γ-tocopherol, while downregulation of creatinine, threonate in GC group, indicating that GC patients were obviously involved in oxidative stress, and perturbed metabolism of amino acids and fatty acids. Conclusion: The metabolic phenotype of CSG is significantly different from GC, while that of IM is similar to it. The discriminatory metabolites characterizing progressive stages from CSG to GC might be the potential markers to indicate a risk of GC.