Expression and Clinical Significance of TM9SF3 in Lung Adenocarcinoma

Objective To investigate the expression and clinical significance of TM9SF3 in lung adenocarcinoma (LUAD). Methods TCGA and GEPIA databases were used to screen the differentially-expressed TM9SF family molecules and analyze their effects on patient prognosis with LUAD. The expression and localization of TM9SF3 in LUAD patients were verified by a human proteomic mapping database, Western blot assay, and polymerase chain reaction assay. Herein, the GSEA was used for the signal pathway enrichment analysis of TM9SF3-related genes. Meanwhile, the TIMER database and CIBERSORT algorithm were used to analyze the correlation between differentially-expressed TM9SF3 and the degree of immune cell infiltration. Results The expression of TM9SF3 in LUAD was significantly increased and had a significant adverse effect on the prognosis of LUAD patients. In addition, immunoblotting and polymerase chain reaction confirmed that TM9SF3 was highly expressed in LUAD. Meanwhile, the genes related to TM9SF3 expression were mainly enriched in cell signaling pathways regulating immune cell activity. The expression of TM9SF3 was significantly correlated with the expression changes of six immune cells. Conclusion TM9SF3 is differentially expressed in LUAD and may be used as a potential prognostic marker for LUAD patients. TM9SF3 can also change the level of immune cell infiltration in LUAD patients and is expected to be a new potential target for LUAD immunotherapy.