Abstract: Objective To investigate the expression of erythropoietin-producing hepatocellular receptor A5 (EPHA5) in lung adenocarcinoma. 
Methods The variation of EPHA5 in different tumors was obtained through the network database, and the EPHA5 protein interaction network diagram was constructed to analyze the prognosis of EPHA5 in lung adenocarcinoma. The surgical specimens and clinical data of patients with lung adenocarcinoma were collected. The expression of EPHA5 was detected by immunohistochemistry, and the correlation between EPHA5 expression in lung adenocarcinoma and clinical characteristics of patients was analyzed. 
Results EPHA5 has the highest mutation frequency in lung adenocarcinoma, mainly missense mutations. In addition to the ligands of EPH family, EPHA5 was closely related to RhoA and ADAM10 proteins. High expression of EPHA5 was associated with overall survival and time to first progression in patients with lung adenocarcinoma. EPHA5 expression was up-regulated in lung adenocarcinoma tissues, which was significantly correlated with lymph node metastasis, differentiation degree and TNM stage. 
Conclusion EPHA5 is highly expressed in lung adenocarcinoma tissues, which can be used as a prognostic factor for lung adenocarcinoma. 

Key words: lung adenocarcinoma, immunohistochemistry, data mining