| BackgroundGastric cancer has the fifth incidence rate and the third mortality rate among all malignant tumors.China is a country with heavy disease burden of gastric cancer,bearing about 400,000 new cases every year,which accounts for 42%of the new cases all over the world.It has been universally acknowledged that to discover early,diagnose early and treat early is the key to improve the prognosis of gastric cancer.Digestive endoscopy has a good diagnostic ability but is limited in screening publics for it is invasive,complicated and time-consuming.Recent years,researches have been carried out in finding altered metabolism of phospholipids and its byproducts in different kinds of tumors,including gastric cancer.As potential biomarkers of gastric cancer,phospholipid metabolism hasn’t been fully illuminated with a small number of related studies published.MethodsWith the technology of MALDI-FTICR MS,we analyzed the serum from five group of patients(control group,atrophic gastritis or intestinal metaplasia group,low grade of intraepithelial neoplasia group,high grade of intraepithelial neoplasia group,early gastric cancer group,22 cases of each group and 110 cases in all)in training group.Comparisons were made between groups to find the altered phospholipids.Area under curves(AUCs)were obtained with receiver operating characteristic curves(ROC)for each phospholipid.The analyses were repeated for patients in validation group(control group,early gastric cancer group).Different phospholipids and their diagnostic efficiency were verified.With serum from early gastric cancer patients in the validation group,we also examined the difference between pre-surgery samples and post-surgery samples.ResultsNineteen kinds of phospholipids were identified and analyzed in this research.In the training group,eight kinds of phospholipids were found to have different levels among groups,which includes PA(36:3),PA(38:5),PC(32:0),PC(34:3),PC(36:1),SM(24:1),SM(34:1)and SM(36:1).SM(24:1)and SM(34:1)had an increasing trend from control group to early gastric cancer group,while PC(32:0),PC(34:3)and SM(36:1)displayed the highest level in two intraepithelial neoplasia groups.When using single phospholipid to distinguish control group,atrophic gastritis or intestinal metaplasia group from intraepithelial neoplasia groups and early gastric cancer group,the AUC of SM(34:1)、SM(36:1)was 0.806 and 0.811,respectively.When using a combination of different phospholipids,the AUC was 0.915,with a sensitivity of 0.879 and specificity of 0.864.Some phospholipids showed similar results when the analyses were repeated in the validation group,which includes SM(24:1),SM(34:1)and SM(36:1).All of them were significantly increased in the early gastric cancer group.Six different phospholipids were identified to be different between pre-surgery and post-surgery samples,among which SM(34:1)、SM(36:1)were significantly decreased after surgery.ConclusionsPhospholipid metabolism was significantly changed among the gastric cancer patients.Serum phospholipids can better distinguish early gastric cancer and intraepithelial neoplasia from control and atrophic gastritis or intestinal metaplasia,which might be valuable in serving as a good diagnostic marker.At the same time,serum phospholipids could also help to monitor tumor recurrence after surgery. |
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