Integrin α-5 as a potential biomarker of head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) is one of the most common malignant tumors that endanger human health. In recent years, the incidence of HNSCC has been increasing, without any significant improvement in the prognosis. Therefore, increased knowledge on the molecular mechanism underlying HNSCC development will allow the development of new strategies for therapy. The present study attempted to identify key genes involved in HNSCC development. Expression profiles of HNSCC and normal samples were downloaded from The Cancer Genome Atlas database. Differentially expressed genes (DEGs) between the HNSCC and normal samples were identified and subjected to Gene Oncology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis. A protein-protein interaction (PPI) network was constructed, and Cytoscape CentiScape and Gene Expression Profiling Interactive Analysis were used to identify key DEGs. Finally, expression profiles of HNSCCs, including 500 HNSCCs and 44 normal samples, were included in the analysis. A total of 1,181 DEGs were screened, among which 354 genes were upregulated and 827 genes were downregulated in HNSCC compared with normal tissues. The GO enrichment analysis showed that the DEGs were mainly involved in chloride transmembrane transporter, metalloendopeptidase and substrate-specific channel activities. The KEGG pathway analysis revealed that the DEGs were mainly associated with 'protein digestion and absorption', as well as 'extracellular matrix-receptor interaction'. Integrin α-5 (ITGA5) was identified as a hub gene, based on the PPI network complex, and was confirmed to be significantly associated with the overall survival rate. Moreover, ITGA5 was overexpressed specifically in HNSCC. The genes found, notably ITGA5, are potential diagnostic biomarkers and therapeutic targets in HNSCC.