miR-15a and miR-24-1 as putative prognostic microRNA signatures for pediatric pilocytic astrocytomas and ependymomas.

ABSTRACT

In the current setting, we attempted to verify and validate miRNA candidates relevant to pediatric primary brain tumor progression and outcome, in order to provide data regarding the identification of novel prognostic biomarkers. Overall, 26 resected brain tumors were studied from children diagnosed with pilocytic astrocytomas (PAs) (n = 19) and ependymomas (EPs) (n = 7). As controls, deceased children who underwent autopsy and were not present with any brain malignancy were used. The experimental approach included microarrays covering 1211 miRNAs. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to validate the expression profiles of miR-15a and miR-24-1. The multiparameter analyses were performed with MATLAB. Matching differentially expressed miRNAs were detected in both PAs and EPs, following distinct comparisons with the control cohort; however, in several cases, they exhibited tissue-specific expression profiles. On correlations between miRNA expression and EP progression or outcome, miR-15a and miR-24-1 were found upregulated in EP relapsed and EP deceased cases when compared to EP clinical remission cases and EP survivors, respectively. Taken together, following several distinct associations between miRNA expression and diverse clinical parameters, the current study repeatedly highlighted miR-15a and miR-24-1 as candidate oncogenic molecules associated with inferior prognosis in children diagnosed with ependymoma.