SPAG5 Expression Correlated With Prognostic Implication and Immune Infiltration in Lung Adenocarcinoma

Background: Sperm-associate antigen 5 (SPAG5) is a critical oncogene in several cancers. But the role of SPAG5A in lung adenocarcinoma (LUAD) remains unclear. Thus, the aims of our study are to explore the function and underlying mechanism of SPAG5 in LUAD. Methods: Expression of SPAG5 was determined using the Oncomine, TIMER, and GEPIA databases. Correlation of SPAG5 and survival was detected by GEPIA database, PrognoScan, Kaplan-Meier Plotter databases. And the association between SPAG5 and tumor malignant phenotypes were analyzed by the CancerSEA. Besides, the correlation between SPAG5 expression and tumor immune infiltration as well as immune checkpoints were analyzed by TIMER. the co-expression genes of SPAG5 were identified using STRING, and the mutation and biological function of SPAG5 and its co-expression genes were determined by cBioPortal and Metascape, respectively. Finally, the SPAG5 expression in LUAD samples was determined by tissues microarrays (TMA) and immunohistochemistry (IHC) analyses. Results: We found that upregulated SPAG5 associated with poor survival of LUAD patients. Besides, SPAG5 expression associated to B cell, CD4+ cell, CD8+ cell, macrophage, DC cell as well as CD274, CTLA4, GZMB, LAG3, PDCD1, TIGIT in LUAD. SPAG5 expression also associated with cell proliferation, cell cycle, DNA damage and repair, epithelial-mesenchymal transition (EMT), invasion, and stemness, inflammation in LUAD. Conclusion: Our finding indicated that SPAG5 acted as a crucial oncogene in LUAD, and correlated with unfavorable survival as well as tumor infiltration inflation.