High Expression of AMIGO2 Is an Independent Predictor of Poor Prognosis in Pancreatic Cancer
Authors: jing zhang , feng Fu xi 
Published: June 2021

Abstract
Background.The AMIGO2 extracellular domain has a leucine - rich repetitive domain (LRR) and encodes a type 1 transmembrane protein , and is a member of the AMIGO gene family .Although the abnormal expression of AMIGO2 is associated with multiple tumors , the relationship with pancreatic cancer is not clear .Methods.The expression of AMIGO2 mRNA and proteins in pancreatic cancer was analyzed using NCBI GEO database and GEPIA2、Human Protein Atlas database.The RNA sequencing data of pancreatic cancer and clinical data of pancreatic cancer patients in TCGA public database were retrospectively analyzed. AMIGO2 gene expression data and their corresponding clinical information in the sample were analyzed retrospectively. The diagnostic value of AMIGO2 expression in pancreatic cancer patients was determined by receiver operating characteristic (ROC) curve analysis. The effects of AMIGO2 expression differences on survival time of pancreatic cancer patients were analyzed by Kaplan-Meier Plotter database and GEPIA2 database.The correlation between AMIGO2 gene and TP53 mutation in pancreatic cancer was analyzed by UALCAN database and TIMER database. The similar genes of AMIGO2 in pancreatic cancer were analyzed by GEPIA2 database, and the biological behavior, cellular composition, molecular function enrichment analysis and protein interaction of similar genes were analyzed by DAVID database and Metascape database. enrichment analysis of AMIGO2 similar gene pathways using KEGG database. The MSIGDB cancer coexpression module in Harmonizome database and TIMER database were used to study the gene coexpression of AMIGO2 in pancreatic cancer. AMIGO2 transcription factors were predicted using the JASPER database. The pathway of AMIGO2 transcription factors and co-expression genes was studied by KEGG database.Results. The expression of AMIGO2 (GSE16515, GSE15471) in pancreatic cancer tissues was significantly higher than that in normal tissues (P < 0.05). The GEPIA2 database also confirmed that the expression of AMIGO2 in pancreatic cancer tissues was significantly higher than that in normal tissues. The expression level of AMIGO2 gene was correlated with lymph node metastasis and histological grade of pancreatic cancer (P<0.05). The high expression of AMIGO2 protein in pancreatic cancer was confirmed in Human Protein Atlas database. The overall survival rate and progression-free survival rate of pancreatic cancer patients with high expression of AMIGO2 were significantly shorter than those of patients with low expression of AMIGO2 in Kaplan-Meier Plotter database and GEPIA2 database. In the gene ontology analysis, it is found that AMIGO2 is involved in cell adhesion, proliferation, migration, apoptosis and other biological processes. KEGG analysis pathway is concentrated in the focal adhesion pathway, mitotic cell cycle changes, and the regulation of cell protein localization. Abnormal expression of AMIGO2 was found in pancreatic cancer caused by TP53 mutation in UALCAN and TIMER databases.In JASPAR database, we predicted that there are 10 transcription sites between AMIGO2 and transcription factor MYB. In addition, there are positive genes related to AMIGO2 in TIMER database and transcription factor MYB regulates tumor cell proliferation and apoptosis in PI3K-Akt signal transduction pathway and WNT signal pathway in pancreatic cancer.