Abstract 1806: Global analysis and validation of miRNA levels in cerebrospinal fluid of brain tumor patients
Authors: Kopkova Alena , Sana Jiri , Vecera Marek , Machackova Tana , Fadrus Pavel , Kovacova Julia , Slaby Ondrej 
Published: August 2019

Abstract
Introduction. Incidence rate of primary brain tumors and brain metastases counts yearly around 40 patients per 100 000 persons in the world and is still growing. Prognosis and therapy differs between brain tumor types and, therefore, accurate and early diagnosis might improve survival and life quality of patients. However, current diagnostic approaches are limited by localization and tissue heterogeneity of brain tumors. Cerebrospinal fluid (CSF) bathes central nervous system (CNS) and thus is supposed to reflect all pathological conditions. From this perspective, CSF looks as ideal source of diagnostic biomarkers of brain tumors. MicroRNAs, short non-coding RNAs involved in the pathogenesis of many cancers including brain tumors, might represent group of new biomarkers. In addition, dysregulated levels of brain tumor specific miRNAs have been already observed also in CSF. Following these facts, analysis of CSF miRNAs in brain tumor patients promises a new diagnostic approach enabling more accurate diagnosis.
Material and methods. Next-generation sequencing was performed for analysis of small RNAs in 89 CSF samples taken from 32 GBM, 14 low-grade glioma (LGG), 11 meningioma, 13 brain metastasis patients and 19 non-tumor donors. CleanTag Small RNA Library Prep Kit (TriLink BioTechnologies) was used for cDNA library preparation. NextSeq 500 instrument together with Next 500/550 High Output v2 Kit - 75 cycles (both Illumina) were used for final sequencing analysis. Subsequently, according to NGS results we measured levels of 13 miRNAs in independent set of CSF samples (35 GBM, 42 meningiomas, 8 metastasis patients and 19 control) using TaqMan Advanced miRNA Assays (ThermoFisher Scientific).
Results. NGS analysis revealed 25, 3, 2 and 14 CSF miRNAs significantly differently expressed in GBM, meningiomas, LGG and metastasis patients (p &lt; 0.001, for LGG p &lt; 0.05), respectively, in comparison with control CSF samples. In addition, 6 miRNAs showed different levels between GBM and LGG (p &lt; 0.05). Subsequent validation of selected CSF miRNAs has confirmed different levels of 7 miRNAs in GBM (miR-10a, miR-196a, miR-196b, miR-30e, miR-30c, miR-7b, miR-7c), 3 in meningioma (miR-140, miR-21, miR-30e) and 2 in brain metastasis (miR-30e and miR-7c) compared to control CSF samples (p &lt; 0.05). Validation of miRNA levels in LGG CSF samples is in progress and will be part of the poster presentation.
Conclusion. We have observed that CSF from patients with various brain tumors (GBM, LGG, meningioma, and brain metastasis) is characterized by specific miRNA signature. Our results suggest potential of CSF miRNAs to be useful biomarkers in brain tumors. This work was supported by Ministry of Health of the Czech Republic grant nr. NV18-03-00398, grant of Czech Grant Agency nr. 17-17636S and by the Ministry of Education, Youth and Sports of the Czech Republic under the project CEITEC 2020 (LQ1601).
Citation Format: Alena Kopkova, Jiri Sana, Marek Vecera, Tana Machackova, Pavel Fadrus, Julia Kovacova, Ondrej Slaby. Global analysis and validation of miRNA levels in cerebrospinal fluid of brain tumor patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1806.