| OBJECTIVE:At present,a large number of studies have shown that microRNA-421 may be a non-invasive biomarker for early diagnosis,screening and prognosis prediction of gastric cancer,which has the characteristics of high detection rate,high preservation rate and high stability.However,inconsistent results between studies hindered its application in clinical practice.Based on this topic,we conducted a meta-analysis of miR-421 in a collection of English literature studies to evaluate the diagnostic efficacy of miR-421 as a biomarker for early diagnosis of gastric cancer.At the same time,in order to explore the mechanism of miR-421 expression in gastric cancer and the mechanism of miR-421 to promote the occurrence and development of gastric cancer,to find key genes for early diagnosis,clinical treatment and prognosis of gastric cancer,this topic systematically describes Horizontal function.METHODS:Using PubMed,Web of Knowledge,Cochrane Libriry,Embase,Wanfang,Weipu and HowNet as the literature screening targets,we searched for the existing research involving miR-421 four grid table data in the diagnosis of gastric cancer.According to the inclusion and exclusion criteria of the literature,two researchers who did not interfere with each other selected the literature.The researchers sequentially extracted data from the selected studies and evaluated the quality of the studies.Use StataSE(14.0),Review Manager 5.3 and Meta-DiSc(1.4)and other statistical software for data processing of the four grid table.In addition,this subject downloads the gastric cancer miRNA-Seq expression profile in the TCGA database and analyzes the expression of miRNA in GC.Predict miR-421 targets through the target gene website,and use the Draw Venn Diagram online website to take intersections,thereby increasing the accuracy of the target.Use the bioinformatics method to analyze the biological functions and related approaches involved in the target in the DAVID 6.8 database.Finally,use STRINGC software to explore the main relevant PPI network of the target encoding protein,identify the key role of the PPI network,and explore the biological functions and pathways involved in miR-421 and its targets;The expression of key target genes in patients with gastric cancer finds targets for early diagnosis,clinical treatment,and prognosis of gastric cancer.RESULTS:According to the inclusion criteria and exclusion criteria,this article finally included three articles,a total of five sets of data,including 430 patients with gastric cancer and 386 healthy controls.Meta analysis conclusions suggest that the overexpression of miR-421 in GC,the combined sensitivity and specificity of miR-421 for the diagnosis of gastric cancer are 0.93(95%CI:0.90?0.95),0.71(95%CI:0.45?0.88);Positive likelihood ratio and negative likelihood ratio were 3.25(95%CI:1.47?7.16),0.10(95%CI:0.06?0.15);the diagnostic odds ratio was 33.42(95%CI:10.79?103.54),under the SROC curve The area is 0.93;given a priori probability of 50%,the posterior probabilities of positive and negative tests are 76%and 9%.In this project,a total of 306 up-regulated or down-regulated miRNAs were found using TCGA database and R language.Among them,miR-421 was up-regulated in gastric cancer tissues.In addition,the subject also predicted a total of 599 related targets through two target gene prediction databases,miRanda and miRDB.GO functional annotation analysis and KEGG pathway enrichment analysis results suggest that miR-421 target genes are enriched in biological functions such as nucleoplasm,nucleus,protein binding and mRNA monitoring pathways,MAPK signaling pathways,dopamine synaptic pathways and other pathways.Because the target gene and the encoded protein affect each other,this topic sets relevant parameters in the constructed PPI network,and screens out some of the more prominent PPI networks containing 37 proteins.At the same time,relevant parameters were set in the outstanding PPI network that was further screened out,and ten key genes were screened out,namely SMAD4,ATM,RBBP7,POLR2D,CASP3,UBE2D3,JARID2,XIAP,HOXA9 and GMNN.The analysis results show that the expression of key genes in gastric cancer tissues is significantly higher than that in adjacent tissues.CONCLUSION:The expression of miR-421 in gastric cancer is significantly increased,and the efficacy of diagnosing gastric cancer is good.It can be used as one of the auxiliary reference indicators for early diagnosis and biological behavior of gastric cancer.The bioinformatics method can effectively screen and analyze the differentially expressed miRNA in GC,which is convenient for further exploring the proliferation,invasion and transfer of GC,and looking for new targets.The high expression of miR-421 in gastric cancer tissues may be related to its target genes,confirming the application value of miR-421 as a biomarker for GC diagnosis. |
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