Investigation of Potential Mechanisms Associated with Non-small Cell Lung Cancer

This study aimed at investigating the crucial mechanisms underlying non-small cell lung cancer (NSCLC). NSCLC-related microarray data GSE27262 were downloaded from Gene Expression Omnibus, including 7 NSCLC 1a samples, 18 NSCLC 1b samples, and their matched normal samples. The common differentially expressed genes (DEGs) between NSCLC 1a and NSCLC 1b samples were identified, followed by protein-protein interaction (PPI) network construction, functional enrichment analysis, and weighted gene co-expression network analysis (WGCNA). Further, the key DEGs were confirmed based on the lung adenocarcinoma (LUAD) data from the Cancer Genome Atlas (TCGA) database, followed by clinical prognostic analysis. There were 802 (NSCLC 1a) and 734 (NSCLC 1b) DEGs identified. By intersection analysis, we obtained 255 upregulated and 97 downregulated common DEGs. Upregulated DEGs were significantly enriched in the plasma membrane and extracellular region, whereas the downregulated DEGs were significantly enriched in the cytoskeleton and cell cycle process. Topoisomerase (DNA) II alpha (TOP2A) and cyclin B1 (CCNB1) were hub nodes in the PPI network. Based on WGCNA, 5 modules were obtained. In the module MEgreen, DEGs were significantly enriched in cytokine-cytokine receptor interaction and focal adhesion. Notably, 1797 DEGs were identified based on the LUAD data from the TCGA database; among them, 285 DEGs were common DEGs identified from GSE27262 data. Upregulation of TOP2A and CCNB1 was correlated with poor survival of patients. The hub genes and key pathways identified in this study are helpful for a comprehensive knowledge of the molecular mechanisms of NSCLC.