The current management of ependymoma is wrought with limitations. Molecular classification is a promising development. MicroRNA (miRNA) deregulation is associated with human cancer and may be a means of molecular classification. The aim of our study is to investigate the association of miRNA expression with the clinicopathologic characteristics of ependymoma. Twenty-two samples were clinically annotated. Histologic features were reassessed and the expression of Ki-67, cyclin D1, and nestin was examined. The expression of 84 stem cell-related miRNAs was profiled. The ΔΔCT method and a Student's t test were used to compute fold changes and P values, respectively. Our analysis revealed 24 statistically significant associations. We identified seven site-specific miRNAs. The pattern of expression was variable in each anatomic site. In addition, we identified six candidate recurrence biomarkers, all of which were overexpressed in recurrent cases. All three grade-related miRNAs were underexpressed in anaplastic samples. Two miRNAs each were underexpressed in samples immunoreactive to Ki-67 and cyclin D1. No miRNAs were differentially expressed between nestin-negative and nestin-positive samples. In conclusion, molecular alterations in ependymoma involve miRNAs. In our report, we review the level of evidence for the biomarker candidacy of identified miRNAs. Confirmatory studies are necessary to establish robust biomarkers for the clinical management of ependymoma. Proteins regulated by differentially expressed miRNAs are additional candidate biomarkers and may offer targets for novel therapeutic interventions.
Keywords: Biomarkers; Ependymoma; Gene expression profiling; MicroRNAs; PCR Array; Real-time PCR.