Objective: To investigate the differentially expressed genes between gastric cancer and normal gastric mucosa by bioinformatics analysis, identify the important gene participating in the occurrence and progression of gastric cancer, and predict the functions of these genes.
Methods: The gene expression microarray data GSE100935 (including 18 gastric cancer samples and normal gastric mucosal tissues) downloaded from the GEO expression profile database were analyzed using Morpheus to obtain the differentially expressed genes in gastric cancer, and a cluster analysis heat map was constructed. The online database UALCAN was used to obtain the expression levels of these differentially expressed genes in gastric cancer and normal gastric mucosa. The prognostic value of the differentially expressed genes in gastric cancer was evaluated with Kaplan-Meier survival analysis. GO functional enrichment analysis was performed using Fun-Rich software, and the STRING database was exploited to establish a PPI network for the differentially expressed genes.
Results: A total of 45119 differentially expressed genes were identified from GSE100935 microarray data. Analysis with UALCAN showed an obvious high expression of EXD3 gene in gastric cancer, and survival analysis suggested that a high expression level of EXD3 was associated with a poorer prognosis of the patients with gastric cancer. GO functional enrichment analysis found that the differentially expressed genes in gastric cancer were involved mainly in the regulation of nucleotide metabolism and the activity of transcription factors in the cancer cells.
Conclusions: EXD3 may be a potential oncogene in gastric cancer possibly in relation to DNA damage repair. The up-regulation of EXD3 plays an important role in the development and prognosis of gastric cancer, and may serve as an important indicator for prognostic evaluation of the patients.
目的: 通过生物信息学分析研究胃癌与正常胃粘膜间具有差异性表达的基因，找出参与胃癌发生发展及预后的关键基因，并对其所涉及的功能进行分析预测。
方法: 从GEO表达谱数据库中下载表达谱基因芯片数据GSE100935（包括18例胃癌样本及正常胃粘膜组织），利用Morpheus在线软件分析基因芯片GSE100935的数据，获得在胃癌与正常胃粘膜组织中存在差异表达的基因，并构建聚类分析热图；利用软件UALCAN在线分析差异表达基因在胃癌与正常胃粘膜组织中表达水平；利用KaplanMeier绘图软件对差异表达基因在胃癌患者中的表达高低进行生存分析；最后采用Fun Rich软件进行GO功能富集分析，网站STRING构建目的基因蛋白互作网络。
结果: 通过分析基因芯片GSE100935获得45119个差异表达的基因；在线分析软件UALCAN显示EXD3基因在胃癌组织中高表达；同时生存分析提示当EXD3基因高表达时，胃癌患者的预后相对较差；GO功能富集分析发现，差异表达基因主要与胃癌细胞核苷酸的新陈代谢调节以及转录因子的活动有关。
结论: EXD3可能是胃癌中潜在的癌基因，可能与DNA损伤修复有关，其表达上调在胃癌的发生发展及预后过程发挥重要作用，并有望成为判断胃癌患者预后的重要的生物学指标。
Keywords: EXD3; bioinformatics analysis; gastric cancer; prognosis.