A Protetomic Difference Study On Gastric Cancer Between Early And Advanced Patients

Objective Gastric cancer is one of the most common world’s malignant gastrointestinal tumors,to achieve early detection、early diagnosis and early gastric cancer therapeutic purposes, thereby can significantly improve the prognosis of patients and improve their survival.Now the gastric tumor marker like CEA, CA199, CA724 and other, which were widely used in clinical, its sensitivity and specificity are not ideal, and relatively specific marker in gastric tumor were discoveried in recent year like MG7-antigen and pepsinogen, there is no large sample of gastric cancer screening in our country. Therefore, our study intends to use isotopic labeling by the relative and absolute quantification(i TRAQ) combined liquid chromatography tandem mass spectrometry(LC-MS / MS) proteomics technology to screen differentially expressed proteins in serum of the Early and advanced gastric cancer as well as healthy people, and after use bioinformatic analysis to screen of the specific proteins which were associated with development of gastric cancer. Finally, use Western blot and immunohistochemistry method to validate these proteins, in order to find associated with the stage and prognosis of gastric cancer’s protein markers.Methods Use i TRAQ quantitative proteomics to analyze advanced and early gastric cancer patients all three cases and two cases of healthy controls serum, landing GO and KEGG database to identify proteins by bioinformatic analysis. Selecte differences expression proteins through different expression and bioinformatics analysis combined with literature review, choose those proteins which are related with progression, signal transduction pathways and associated with the invasion and metastasis of gastric cancer.Serum samples from 30 patients early, advanced gastric cancer and normal control group were randomly selected in each of nine cases of serum using Western blot technique on one of two different proteins for validation. Another collection and early gastric carcinoma of advanced gastric cancer postoperative serum corresponding paraffin embedded and adjacent normal tissue 30 cases each, immunohistochemical methods for two different proteins for validation. Finally, use statistical software SPSS16.0 with t test and Kaplan-Meier survival analysis, analysis of the relationship between the expression of two different proteins in patients with gastric cancer recurrence and metastasis and its influence on the prognosis.Results With i TRAQ quantitative proteomics method to obtain a total of 119 differentially expressed proteins identified(53 up-regulated and 66 down-regulated).Login GO database search found differences in protein mainly located in the cell cytoplasm, organelles and cell membrane, and so on.Its function associated with binding, catalysis, enzyme regulation. Physiological and pathophysiological processes are involved in signal transduction pathways, metabolism, single-cell biological processes, antioxidant, adjusting channels, and so on.Login KEGG pathway database searches, which are mainly involved in MAPK signaling pathway, P53 signaling pathways. According to the conditions to selecte seven key conditions differentially expressed proteins: IGFBP-3, ARF-1, HRG, PON3, FN1, HGF and CETP, moreover to test and verify IGFBP-3 protein and ARF-1 protein.Western blot showed that IGFBP-3 protein expression in advanced gastric serum lower than early gastric cancer and normal serum expression, ARF-1 protein expression in advanced gastric serum were higher than in early gastric cancer and normal control sera of expression, the differences were statistically significant(P <0.05), but the differences between the two proteins in the early and normal control was not statistically significant(P> 0.05). Immunohistochemistry showed that IGFBP-3 protein expression and ARF-1 protein was localized in the cytoplasm and a part of nuclei. IGFBP-3 levels in tissues consistent with the Western blot, ARF-1 in advanced gastric tissues and gastric cancer, consistent with normal tissues compare results with the Western blot results, and the ARF-1 in the early group was also higher than normal levels of expression levels, the difference was statistically significant(P <0.05). IGFBP-3 correlated with recurrence and metastasis of gastric cancer, ARF-1 were correlated with clinical staging, recurrence and metastasis of gastric cancer, the differences were statistically significant(P <0.05). Survival analysis showed: IGFBP-3 average survival time of patients with negative expression was significantly lower than the average survival of patients with positive expression of time, and ARF-1 the average survival time of patients with negative expression was significantly higher than patients with positive expression of the average survival time, the differences were statistically significance(P <0.05).Conclusions Our reserch use i TRAQ quantitative proteomics technology initially screened the differences protein in serum of early gastric cancer, advanced gastric cancer and normal group,finally get the serum differences protein profile in gastric carcinoma, and found a total of 119 different proteins.We screened out seven key different proteinswhich have good diagnostic value:IGFBP-3, ARF-1, HRG, PON3, FN1, HGF and CETP, among them IGFBP-3 is mainly involved in the P53 tumor-related pathway. We verify two different proteins IGFBP-3 and ARF-1, found that the expression of IGFBP-3 protein was down-regulated both in advanced gastric cancer tissue and serum, and related with the recurrence,metastasis and prognosis of gastric cancer;the expression of ARF-1 protein were not only up-regulated in advanced tissue and serum, it also upregulated in the early gastric cancer, and related with clinical stage,ecurrence,metastasis and prognosis of gastric cancer; Our study found that ARF-1 may be a marke greater potential diagnostic value for early and advanced gastric cancer. IGFBP-3 gastric can provide new clues for gastric cancer tumor marker studies, however, the sample size may still need to further expand in the study.