Glioblastoma (GBM) is the most common aggressive brain tumor with a poor prognosis and a median survival time of <15 months. Despite multimodal therapy, including surgical resection and radiochemotherapy, recurrence is common. Until now, recurrence monitoring is based on radiologic imaging but suffers from limited sensitivity. Therefore, circulating “liquid biopsy” markers predicting the time window of recurrence are highly desirable. Abundance-based biomarkers associated with time-to-recurrence will be obtained by analyzing the content of serum-derived extracellular vesicles (EVs) with respect to proteolytic fragments, protease activities, and small RNAs (microRNAs). In addition, a full genomic analysis will be performed to characterize recurrence in individual patients and combine multi-Omics with clinical and imaging data. From these analyses, we aim to identify personalized easy-to-access biopsy markers. With these markers, investigation of pre- and post-surgery serum samples (at time of initial surgery) allows to faithfully discern tumor-originating molecules through their altered abundance in post-surgery samples.
