Weighted Gene Co-expression Network Analysis Identify SCG2 Espression Correlating With Neuroblastoma International Staging System

ObjectiveThe purpose of the study is to dig out the genes of neuroblastoma corralates with risk factors and clinical characteristics through WGCNA,and the International neuroblastoma staging system(INSS),as an important reference factor for risk stratification,is in highlight.Besides,the study also aim to futher explore the possibility of the hub gene as potential therapeutic targets and biomarkers of prognostic assessment of neuroblastoma.MethodsFirstlly,microarrays GSE1313,GSE48022 were downdoaded from GEO(Gene Expression Omnibus)database.GSE13136 contains 30 cases of neuroblastoma used as the experimental group.Selecting GSM1165505,GSM1165506,GSM1165507 and GSM1165508 in GSE48022 as the control group that contain 4 cases of human Bone marrow mesenchymal stem cells.Secondly,after unitary processing,screen profiles by GO and KEGG enrichment analysis to seclect the differentially expressed genes(DEGs).Thirdly,build a weighted gene co-expression network analysis(WGCNA)network which connets the gene modual and clinical characteristics.Then selesct the gene modual connects with INSS staging as aimed modual.Fourthly,construct PPI network of the DEGs in aimed modual and select the genes both show in WGCNA network and PPI network as hub gene.Then,search the hub genes’ functions through Gene batabase to confirm the aimed gene.Finally,validate the aimed gene in Oncomine database and through immunohistochemistry.ResultsCompared with the control group,the DEGs concludes 284 up-regulated genes and 3887 down-regulated genes in the experimental group.Six gene modules were identified by dynamic shearing tree method.Select the yellow module as interested module which related to INSS(r =-0.39,P =0.03).The GO analysis of the yellow gene module showed that the gene function was enriched in 1.Clathrin recruitment(ATCAY,STMN4;P = 0.006178);2.Neuron development(ATCAY,STMN4;P ＝0.04667);3.Secretion of granules(CHGB,SCG2;P =0.039881).The hub genes are CHGB and SCG2.CHGB is mainly related to heart failure and acute respiratory failure[1,2],which may be meaningless for the neuroendocrine tumors.SCG2 is associated with the staging of prostate cancer and pheochromocytoma[3,4].Therefore,SCG2 was selected as the aimed gene.Oncomine database verification showed that SCG2 expression is negatively linear correlated with INSS(R2 =0.242649,P=1.67×10-7).SCG2 is mainly distributed in the cytoplasm of tumor tissues in adrenal tissues and is not expressed in tumor stoma,it’s expression is specific.With the increasing of neuroblastoma INSS stage,the mean optical density of SCG2 protein expression decreased,and the difference was statistically significant(Χ2=18.039,P=0.001).The mean optical density of SCG2 protein expression in malignant pheochromocytoma was lower than the benign pheochromocytoma,and the difference was statistically significant(U=0.000,P=0.020).The mean optical density of SCG2 protein expression in benign pheochromocytoma was similar to that in neuroblastoma stage 1,and the difference was not statistically significant(t=0.719,P=0.488).Conclusion(1)SCG2 expression is linear negatively correlated with neuroblastoma INSS stage,and its up-regulate expression may induce further differentiation of neuroblastoma cells.(2)SCG2 can be one of the biological markers for risk assessment and prognosis prediction of neuroblastoma.(3)SCG2 can be a biological marker to identify the benign and malignant pheochromocytoma.