Analysis of microRNA expression in glial tumors by using a peptide nucleic acid-based microarray

Purpose: Glial tumors are the most common primary brain tumors. However, their characteristics and prognosis are difficult to discern. There is currently an emphasis on microRNAs (miRNA) as candidate biomarkers for glial tumors. The aim of this study is to identify the specific miRNA patterns in glial tumors by using peptide nucleic acid (PNA)based microarrays in an assortment of glial tumors and normal tissue samples. Methods: Sample files were retrospectively assessed for cases diagnosed as glial tumors at the pathological archives of two institutes. miRNAs of 28 cases of glial tumors were analyzed by microarray. In order to verify the results, quantitative real-time polymerase chain reaction (RT-PCR) was performed. miRNA expression was calculated using the 2 method. The expression level of the miRNAs was compared using SPSS version 20.0 (IBM Co.). Results: miRNA expression profiling of glial tumors revealed that 62 miRNAs were detected from glioblastoma and benign brain tissue, with different expression patterns. The expression of miR-296-3p, miR-370, and miR-371-5p was shown to be involved in malignancy. These miRNAs were also increased in the glioblastoma with methylated O6-methyguanine DNA methyltransferase. The expression pattern of miR-296-3p shows same tendency in PNA-based microarray and RT-PCR. Conclusion: These analyses suggest that novel miRNAs can be applicable as diagnostic tools and target therapeutic agents, since miRNAs can positively or negatively regulate glioblastomas.