Next-Generation Sequencing Comparative Analysis of DNA Mutations between Blood-derived Extracellular Vesicles and Matched Cancer Tissue in Patients with IV Grade Glioblastoma

Abstract

The biological heterogeneity of glioblastoma (GBM), the most aggressive type of brain cancer, is a critical hallmark, caused by changes in the genomic mutational asset and influencing the clinical progression over the time. The understanding and monitoring of the mutational profile is important not only to reveal novel therapeutic targets in this set of patients, but also to ameliorate the clinical stratification of subjects and the prognostic significance. As neurosurgery represents the primary technique to manage GBM, it is of outmost importance to optimize alternative and less invasive methods to monitor the dynamic mutation profile of these patients. Extracellular vesicles (EV) are included in the liquid biopsy analysis and have emerged as the biological mirror of escaping and surviving mechanisms by many tumors as well as glioblastoma. Very few studies have investigated the technical feasibility to detect and analyze the genomic profile by Next Generation Sequencing (NGS) in circulating EV of patients with grade IV glioblastoma. Here, we attempted to characterize and to compare with the corresponding matched tissue samples, potential variants with pathogenic significance of the DNA contained in peripheral blood derived EV. The NGS analysis has revealed that patients with grade IV glioblastoma, exhibited lesser DNA content in EV than controls and that both in EV and matched cancer tissues, the NF1 gene was consistently mutated in all patients with the c.2568C>G as the most common pathogenic variant expressed. This study supports the clinical utility of the circulating EV in glioblastoma and as eligible tool for personalized medicine.