Microrna expression distinguish glioblastoma from lower grades astrocytomas (LB286)

Abstract

Astrocytomas are the most common type of adult primary central nervous system neoplasms. The World Health Organization (WHO) histologically classifies astrocytomas into four malignancy grades spanning from grade I, a benign tumor, to grade IV, a highly malignant tumor. This classification is highly subjective and more specific molecular markers are needed. MicroRNAs (miRNAs) are small (19‐24 nucleotides) non‐coding RNAs that regulate gene expression at the post‐transcriptional level. Increased in vitro and in vivo evidence indicates that several miRNAs are dysregulated in all cancers types including astrocytomas. However, the precise miRNAs aberrantly expressed in each astrocytoma grade have not been identified. The aim of this study was to elucidate the miRNAs dysregulated in each astrocytoma grade using formalin‐fixed paraffin‐embedded (FFPE) samples. Microarray data was analyzed with the PARTEK software. Eighty‐five miRNAs were differentially regulated in grade II, 72 miRNAs in grade III and 53 miRNAs in GBM compared with control samples. Particularly, miR‐210, miR‐193b and miR‐27a were highly associated with GBMs. Additionally, up‐regulation of miR‐92b and down‐regulation of miR‐1908 occurred in all astrocytoma grades compared with control individuals. Biological pathway analysis showed a relationship between miRNAs signatures and molecular pathways related with tumor initiation and progression of astrocytoma. Taken together, our results provide additional miRNA signatures to distinguish between GBMs and lower grades of astrocytoma.