Screening and expression verification of key genes in cutaneous squamous cell carcinoma

Background: Cutaneous squamous cell carcinoma (cSCC), a common skin malignancy, often occurs at exposed sites, and patients' appearance after surgical resection can be affected. This study sought to screen the key genes of cSCC via a bioinformatics analysis and explore the clinical significance and possible potential mechanisms of these genes in cSCC. Methods: We screened differentially expressed genes (DEGs) between cSCC and normal skin tissues from the Gene Expression Omnibus database, performed functional enrichment and protein interaction network analyses, and used Cytoscape software to identify the key genes. The expression of the genes was proved by immunohistochemistry. Results: A total of 164 DEGs were screened, and the functional enrichment analysis showed that the DEGs were significantly enriched in deoxyribonucleic acid replication and the cell-cycle pathway. By constructing a protein-to-protein interaction network, kinesin family member 11 (KIF11), aurora kinase A (AURKA), minichromosome maintenance complex component 2 (MCM2), minichromosome maintenance 10 replication initiation factor (MCM10), and denticleless E3 ubiquitin protein ligase homolog (DTL) were identified as 5 key genes with the highest connectivity. The expression of KIF11, AURKA, and MCM2 were investigated by immunohistochemistry. Compared to the normal skin tissues, the positive rates of the KIF11 and MCM2 proteins in the cSCC tissues were 70.0% and 90.0%, respectively, and the difference was statistically significant (P<0.05). The positive rates of AURKA protein expression in the cSCC and normal skin tissues were 13.9% and 0%, respectively, but the difference was not statistically significant. There was no correlation between the above-mentioned 3 key genes. Conclusions: KIF11 and MCM2 were highly expressed in cSCC, and may be involved in tumorigenesis, and represent novel targets for the clinical diagnosis and treatment of cSCC.