Identification and Verification of the Main DifferentiallyExpressed Proteins in Gastric Cancer via iTRAQ Combined withLiquid Chromatography-Mass Spectrometry

Background.Tofind the potential intersections between the differentially expressed proteins and abnormally expressed genes ingastric cancer (GC) patients.Methods. Gastric cancer tissue and adjacent normal mucosa tissue were used for iTRAQ analysis.Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and protein-protein interaction(PPI) analysis were used to evaluate gene function. Western blotting and immunohistochemistry (IHC) were applied to verifythe protein expression.Results. A total of 2770 proteins were identified, of which 147 proteins were upregulated and 159proteins were downregulated. GO analysis revealed that the differentially expressed genes were mainly enriched for the terms“cellular process,”“binding,”and“cell.”The results of the KEGG analysis showed that the most abundantly enriched proteinswere involved in the“focal adhesion”pathway. The results of the PPI analysis showed that VCAM1 was located at the center ofthe PPI network. Western blotting and IHC analysis demonstrated that VCAM1, FLNA, VASP, CAV1, PICK1, and COL4A2were differentially expressed in GC and adjacent normal tissues, which was consistent with the results of the iTRAQ analysis.Conclusion. In conclusion, 6 highly differentially expressed proteins were identified as novel differentially expressed proteins inhuman GC. This exploratory research may provide useful information for the treatment of gastric cancer in the clinic