Evaluation of significant gene expression changes in congenital and acquired cholesteatoma

Etiopathogenesis of acquired and congenital cholesteatoma is still unclear. The clinical behavior of adult acquired, pediatric acquired and congenital cholesteatomas show differences. The scope of the this study was to detect the matrix metalloproteinase (MMP), tissue inhibitors of metalloproteinase (TIMP) and epidermal growth factor receptor (EGFR) gene expression changes in cholesteatoma perimatrix and to compare these changes among congenital cholesteatoma, adult acquired cholesteatoma and pediatric acquired cholesteatoma. A total of 16 genes including MMPs, TIMPs and EGFR were analyzed in the samples of 32 cholesteatoma tissues. Real-time PCR was used for detection of the gene expression levels. Data analyses were achieved by ΔΔCT method (Light Cycler 480 Quantification Software) and Statistical Package for Social Sciences (SPSS) version 22.0. The expression levels of MMP-2, -9, -10, -11, -13, -14, -15, -16 and EGFR genes were significantly higher in acquired cholesteatoma than healthy tissue (p < 0.05). There was a statistically significant decrease (3.34 times more) in the mean TIMP-2 gene expression level in acquired cholesteatoma compared to healthy tissue (p < 0.05). There was a significant increase in the mean expression level of MMP-7 gene and a decrease in the mean expression level of TIMP-1 gene (3.12 times more) in congenital cholesteatoma compared to healthy tissue (p < 0.05). This study indicates that increased expression levels of some particular MMP genes and EGFR gene and decreased expression levels of TIMP genes may play an important role in the development of cholesteatoma. Further, MMP-9, MMP-13 and MMP-14 genes may have a remarkable role in the development of more aggressive cholesteatoma forms. The authors concluded that overexpression of MMP-9, MMP-13 and MMP-14 may cause stronger inflammation associated with cholesteatoma.