The Expression and Prognostic Significance of the Nicotinic Receptor Cluster on 15q25 about CHRNA5 and PSMA4 mRNA in Lung Adenocarcinoma Utilizing TCGA Datasets

Abstract Background: To explore the mutations expression and prognostic significance of 15q25 (CHRNA5 and PSMA4) mRNA in lung adenocarcinoma (LAC) based on immunohistochemistry, TCGA and bioinformatics. Methods: Mutations expression on chromosome 15q25 of 576 primary LAC patients was selected. And their survival and gene expression data were extracted from TCGA. The cell experiment about Beas-2b, A549 and H1299 cell lines were done to further prove the CHRNA5 and PSMA4 expression difference between lung cancer and normal cells. Immunohistochemistry data of CHRNA5 and PSMA4 were detected in LAC and normal tissues from 122 patients.Finally, Gene enrichment analysis (GSEA) was used to predict the regulatory genes of CHRNA5 and PSMA4. Results: CHRNA5 and PSMA4 are frequently mutated in the TCGA (CHRNA5, 1.7%; PSMA4, 1.3%).The expression of CHRNA5 and PSMA4 were obviously higher in A549 and H1299 cells. Immunohistochemical staining revealed that the level of CHRNA5 and PSMA4 was considerably higher in LAC group than in normal group. There was a significant association between high expression of CHRNA5 and Smoking History (P=0.011), Smoking History Pack Year Value(P=0.010). Besides, there was a significant correlation between CHRNA5 and PSMA4 expression level and prognosis (P=0.003; P=0.008),and the higher expression, the worse prognosis. GSEA results suggested that CHRNA5 and PSMA4 high expression samples were respectively enriched to cell cycle, base excision repair, oxidative phosphorylation, protein export, aminoacyl tRNA biosynthesis etc. Conclusions: The expression of CHRNA5 and PSMA4 mRNA has a significant impact on survival of LAC, they may be a potential target for treating patients with lung adenocarcinoma.