Erythropoietin Receptor is a Risk Factor for Prognosis: A Potential Biomarker in Lung Adenocarcinoma

Background: Lung cancer has the highest mortality rate of all cancers, and LUAD's survival rate is particularly poor. Erythropoietin receptor (EPOR) is a member of the cytokine class I receptor family and can be detected in cancers such as lung adenocarcinoma (LUAD), however, the expression levels and prognostic value of EPOR in LUAD are still unclear.Methods: Multiple bioinformatics databases such as TIMER, Kaplan-Meier Plotter and TCGA databases, immunohistochemical method, and clinicopathological data of 92 LUADpatients between January 2008 and June 2016 were used to explore the EPOR expression, gene mutations affecting EPOR expression, EPOR-interacting or coexpressed genes, potential biological functions and the correlation of EPOR expression with prognosis, immune microenvironment and so on.All statistical analyses were performed in the R version 4.1.1.Results: In this study, the EPOR mRNA expression in LUAD tissues was possibly downregulated compared with that in normal lung tissues, but the EPOR protein expression in LUAD tissues was higher than that in paired normal lung tissues. Mutations in five genes, DDX60L, LGR6, POTEB3, RIF1 and SOX5, resulted in downregulation of EPOR expression, mutations in 10 genes includingC1orf168, DBX2 and EIF5B, resulted in upregulation of EPOR expression. Erichment analyses showed that EPOR is involved in neural tissue ligand-receptor interactions, MAPK and PI3K/Akt signaling pathways and cancer pathways. The KM Plotter and PrognoScan databases consistently concluded that EPOR was associated with prognosis in LUAD patients. Our clinicopathological data showed that high EPOR expression was associated with poorer OS (29.5 vs 46 months) and had a good predictive ability for 5-year survival probability. Conclusions: EPOR expression might be downregulated at the mRNA levels and significantly upregulated at the protein levels in LUAD, which showed that the mRNA and protein levels of EPOR are inconsistent.The high expression of EPOR was associated with poor prognosis and is expected to be a potential new prognostic marker for LUAD.