| Objective: Papillary thyroid carcinoma(PTC)is the most common endocrine malignant tumor.Once lymph node metastasis or distant metastasis occurs,it will seriously affect the prognosis of patients with PTC.Therefore,searching for the hub genes related to lymph node metastasis and distant metastasis of PTC is very important for the diagnosis and treatment of PTC.Methods: We obtained the mRNA sequence matrix of PTC and the clinical information of the corresponding samples in The Cancer Genome Atlas(TCGA).The weighted gene co-expression network was used to analyze to construct the co-expression network,and the relationship between gene modules with high correlation among genes and clinical characteristics was established.The module with the highest correlation with lymph node metastasis and distant metastasis was selected.The genes in the module were constructed into Protein-Protein Interaction Networks(PPI)by cytoscape software and the hub genes were screened.Then,the hub genes were screened again through the data sets in GEO and Oncomine databases.Finally,86 pairs of cancer tissues and paracancerous tissues of PTC patients were collected,and the expression of hub genes in PTC was verified by real-time quantitative PCR(RT-qPCR),and the correlation between hub genes and clinicopathological features of PTC patients was analyzed.Results: Nineteen gene modules related to clinical features were established by using WGCNA,among which the magenta gene module had the highest correlation with PTC lymph node metastasis and the midnightblue gene module had the highest correlation with PTC distant metastasis.Using Cytoscape software to visualize PPI and intersect with differentially expressed genes in GSE3678 data set in GEO database,12 hub genes(ARNTL,CDH3,CLDN1,COL8A1,COL8A2,IL1 RAP,LPAR5,PARP4,PERP,PPL,TNFRSF21 and TIAM1)and 10 genes related to PTC distant metastasis(LAMA2,IL6,HTR2 B,HOXB3,H19,GPC3,GAS1,FOXC1,CCL17,LINC00346)were obtained.Then,by comparing the Oncomine data,six hub genes related to lymph node metastasis(CLDN1,COL8A1,COL8A2,IL1 RAP,LPAR5 and GPC3)and three hub genes closely related to distant metastasis of PTC(LAMA2,GPC3 and CCL17)were identified.Finally,the tissue samples of 86 patients with PTC were detected by RT-qPCR.The results showed that the expression of CLDN1,COL8A1,COL8A2,IL1 RAP and LPAR5 in PTC tissues was significantly higher than that in paracancerous tissues,while the expression of GPC3 in PTC tissues was significantly lower than that in paracancerous tissues.There was no significant difference in the expression of the other three genes(CDH3,CCL17 and LAMA2)between PTC carcinoma and paracancerous tissues.Furthermore,the relationship between CLDN1,COL8A1,COL8A2,IL1 RAP,LPAR5,GPC3 and clinicopathological features of PTC was analyzed.It was found that the abnormal expression of these 6 genes in PTC was closely related to cervical lymph node metastasis of PTC.In addition,the expression of LPAR5 was higher in PTC with tumor whose diameter larger than 2cm,while the expression of GPC3 in bilateral PTC was lower than that in unilateral PTC.Conclusion: In this study,we extracted and discovered PTC-related data from TCGA,GEO and Oncomine databases,and verified them in 86 pairs of PTC clinical specimens.Six genes,CLDN1,COL8A1,COL8A2,IL1 RAP,LPAR5 and GPC3,were screened out,which are closely related to lymph node metastasis or distant metastasis of PTC,which provide potential gene targets for the diagnosis and treatment of PTC and a new direction for the study of molecular mechanism related to PTC metastasis. |
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