Tumor Endothelial Marker TEM7 is a Prognostic Biomarker and Correlating with Immune Infiltrates in Gastric Cancer

INTRODUCTION: Tumor endothelial marker 7 (TEM7) is included in the endothelial cells of tumors as a greatly expressed protein. In previous studies, it has been confirmed that TEM7 is highly expressed in gastric cancer (GC) cells and related to tumor invasion and migration. However, the relationship between TEM7 gene expressions, prognostic and tumor-infiltrating lymphocyte in GC is still unclear. METHODS: We obtained the expression of TEM7 in GC tissues using Oncomine and TIMER databases and validated it using qRT-PCR. The effect of TEM7 on survival in patients with GC was explored through the Kaplan–Meier Plotter database. Univariate and multifactorial analyses of the TCGA (The Cancer Genome Atlas) database were performed to explore the association of TEM7 expression with clinical traits. TIMER and GEPIA databases were used to analyze the relationship between TEM7 expression and immune infiltration. GSEA pathway enrichment in Kyoto Encyclopedia of Genes and Genomes (KEGG) exposed possible ways. RESULTS: An expression level of TEM7 was significantly increased in gastric cancer tissues and related with unfavorable survival in GC. Univariate analysis of TCGA (The Cancer Genome Atlas) database indicated that excessive level of TEM7 expression was linked with age, tumor grade and TMN classification, and multivariate analysis indicated that age and level of TEM7 expression were independent prognostic factors for a poor prognosis. The level of expression of TEM7 was positively related to tumor-infiltrating CD4+ and CD8+ T cells, neutrophils, macrophages, and dendritic cells other than B cells in GC. In the end, GSEA pathway enrichment exposed possible ways related to immunity. DISCUSSION: Our study indicates that TEM7 is a prognostic biomarker that makes the decision that the progression of GC and is connected with tumor immune infiltrates in GC.