Oncogenic activation of the HRR pathway drives RAD54L expression in early stage lung adenocarcinoma.

Abstract

e20037 Background: In recent years, there has been a better understanding of ways to use DNA damage and repair (DDR) mechanisms to improve overall sensitivity and/or overcome resistance to traditional DNA damage treatments. The DDR network is quite complex and highly dynamic with as many as 450 proteins integral to the DNA repair. The current study is to identify the key dysregulated genes and its related pathways especially DDR pathways in early progression of lung adenocarcinoma. Methods: TCGA dataset of lung adenocarcinoma (LUAD) including 59 healthy lung tissues and 517 tumor tissues was utilized to detect the differentially expressed mRNAs and lncRNAs. Gene ontology (GO) analysis was conducted with DAVID, while Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of differentially expressed genes was performed using gene set enrichment analysis (GSEA) methods. Results: 41 lncRNAs and 2,047 mRNAs were screened out to be differentially expressed in LUAD. Besides, 38 lncRNAs and 1,801 mRNAs were found to be differentially expressed in T1 stage LUAD. The homologous recombination repair (HRR) pathway was found to be significantly up-regulated in LUAD, with four genes in this pathway up-regulated. In these genes of HRR pathway, PPP4R4 and RAD54L were recognized to be significantly differential expressed in T1 stage, compared with T2 stage and T3 stage, which were putative biomarkers of early stage LUAD. The survival analysis revealed that the expression of RAD54L was significantly related to the survival rate of patients with tumor of T1 stage. Conclusions: HRR pathway was up-regulated in lung adenocarcinoma, in which the expression of PPP4R4 and RAD54L were found to be tumor stage specific and RAD54L was related with survival rate of T1 stage patients. This study provided a further insight into the mechanism of the progression in early stage lung adenocarcinoma.