Over-Expression of EFNA2 in Lung Adenocarcinoma: EFNA2 Gene Expression Correlates with Shortened Survival

Background: The incidence of lung adenocarcinoma (LUAD) is increasing worldwide with different prognosis. Ephrin-A2（EFNA2), a member of the Eph/ephrin family, is associated with tumor progression. However, the correlations of EFNA2 with prognosis in LUAD remain unclear. The purpose of this article is to analyze the impact of EFNA2 on the prognosis of LUAD patients through TCGA, Oncomine, and GEPIA databases, and to explore its possible mechanisms.

Methods: This article found a significant correlation between EFNA2 and shortened survival in LUAD patients through TCGA, Oncomine, and GEPIA database analysis. Therefore, we further invested the relationship between the expression and prognostic value of the EFNA2 gene in LUAD

patients. Sequential data filtering (survival analysis, independent prognostic analysis, and clinicalcorrelation analysis) was performed. EFNA2 expression was analyzed by the Oncomine database and Tumor Immune Estimation Resource (TIMER). We evaluated the influence of EFNA2 on clinical prognosis using Kaplan-Meier plotter, the PrognoScan database and Gene Expression Profiling Interactive Analysis (GEPIA). The correlation between EFNA2 and cancer immune infiltrates was investigated by TIMER. In addition, correlations between EFNA2 expression and gene marker sets of immune infiltrates were analyzed by TIMER and GEPIA. In addition, gene enrichment analysis was performed by Metascape. Finally, a co-expression analysis was performed by the Oncomine database.

Results: A cohort of LUAD patients showed that high EFNA2 expression was associated with poorer overall survival (OS), disease-free survival (DFS) by TCGA, and EFNA2 was significantly associated with stage in LUAD. In addition, EFNA2 expression was positively correlated with infiltrating levels of B cells and CD8+ T cells. Moreover, the differential expression of EFNA2 was significantly higher in lung adenocarcinoma compared with that in normal controls. Specifically, EFNA2 was positively associated with ADAMTSL5, REEP6, PCSK4, C19orf25, and ANAPC2.

Conclusions: Our data indicate that EFNA2 is a potential diagnostic and prognostic biomarker and a promising molecular therapeutic target to attenuate LUAD progression.