MiRNAs Expression Analysis in Paired Fresh/Frozen and Dissected Formalin Fixed and Paraffin Embedded Glioblastoma Using Real-Time PCR

Dario De Biase,Gianluca Marucci,Agostino Baruzzi,Serenella Cerasoli,Cristian Taccioli,Annalisa Pession,Michela Visani,Luca Morandi,Svetlana Kotliarova

doi:10.1371/journal.pone.0035596

Abstract

miRNAs are small molecules involved in gene regulation. Each tissue shows a characteristic miRNAs epression profile that could be altered during neoplastic transformation. Glioblastoma is the most aggressive brain tumour of the adult with a high rate of mortality. Recognizing a specific pattern of miRNAs for GBM could provide further boost for target therapy. The availability of fresh tissue for brain specimens is often limited and for this reason the possibility of starting from formalin fixed and paraffin embedded tissue (FFPE) could very helpful even in miRNAs expression analysis. We analysed a panel of 19 miRNAs in 30 paired samples starting both from FFPE and Fresh/Frozen material. Our data revealed that there is a good correlation in results obtained from FFPE in comparison with those obtained analysing miRNAs extracted from Fresh/Frozen specimen. In the few cases with a not good correlation value we noticed that the discrepancy could be due to dissection performed in FFPE samples. To the best of our knowledge this is the first paper demonstrating that the results obtained in miRNAs analysis using Real-Time PCR starting from FFPE specimens of glioblastoma are comparable with those obtained in Fresh/Frozen samples.

Highlights

MicroRNAs are small (,20–22 nt) non coding RNAs that modulate gene expression at a post-transcriptional level
Each miRNA, playing its role through perfect and nearly perfect complementarity with its target mRNAs, could regulate the expression of about a hundred of genes, influencing a large spectrum of physiological processes as different steps of cellular development, proliferation or apoptosis regulation [1]. Many of these pathways are altered in human neoplasia; it has been demonstrated that miRNAs can act both as oncogenes or oncosuppressors, according to their target mRNAs [2]
MiRNAs analysis starting from formalin fixed and paraffin embedded tissue (FFPE) samples could be of great usefulness for miRNAs expression study

Summary

Introduction

MicroRNAs (or miRNAs) are small (,20–22 nt) non coding RNAs that modulate gene expression at a post-transcriptional level. Each miRNA, playing its role through perfect and nearly perfect complementarity with its target mRNAs, could regulate the expression of about a hundred of genes, influencing a large spectrum of physiological processes as different steps of cellular development, proliferation or apoptosis regulation [1]. Many of these pathways are altered in human neoplasia; it has been demonstrated that miRNAs can act both as oncogenes or oncosuppressors, according to their target mRNAs [2]. Neverthless the progress in neurosurgery, chemio- and radiotherapy, molecular target identification for focused therapy (MGMT), the clinical history of the disease is usually short (less than one year in more than 50% of cases) [8,9]

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Results

Conclusion