Abstract 1991: Circulating tumor cells migrate beyond the central nervous system in glioblastoma multiforme

Abstract Introduction: The concept of liquid biopsy (LB) has garnered significant attention over the past decade, offering the potential to transform cancer care. However, its clinical utility requires further validation through rigorous trials. This study focuses on glioblastoma multiforme (GBM), an aggressive and fatal subtype of central nervous system malignancies. Circulating tumor cells (CTCs), which originate from primary tumors and migrate via peripheral blood to distant sites, are closely linked to tumor spread and recurrence. In GBM, systemic dissemination is rare due to challenges like the blood-brain barrier (BBB), lack of lymphatic drainage, and the disease’s short survival timeframe. Despite these challenges, noninvasive detection of CTCs holds promise for diagnostic, predictive, and prognostic applications. Materials and Methods: Peripheral blood samples from 110 curatively resected GBM patients were collected preoperatively using Cell-Free DNA BCT® tubes (Streck, Inc.) to preserve cell stability. CTC identification was conducted with the CytoTrack CT11TM (2/C) system, a semi-automated immunofluorescence microscopy platform employing glial fibrillary acidic protein (GFAP), vimentin, CD45 immunostaining, and DAPI counterstaining. The tumor origin of CTCs was confirmed through aCGH analysis using DNA extracted from single CTCs and matched FFPE tumor tissues in 10 GBM patients. A preliminary Kaplan-Meier survival analysis was performed on 55 patients with a follow-up period exceeding two years, stratified by CTC presence. Results: We evaluated peripheral blood samples from 110 GBM patients, identifying CTCs or cancer cell clusters in 35% of cases. The aCGH genomic profiling verified the tumor origin of CTCs in 90% of cases (9/10). Kaplan-Meier survival analysis revealed no significant correlation between CTC presence and overall survival of GGM patients. This outcome may be attributed to the generally short survival associated with GBM, which could improve with advancements in oncology and palliative care. Another possibility is the suppression of tumor cell growth outside the CNS. Conclusions: This study confirms the presence of CTCs in the peripheral blood of 35% of GBM patients, although currently without prognostic significance. Patient enrollment and the collection of clinical data are ongoing. Acknowledgments: This work was supported by the European Union - Next Generation EU (LX22NPO5102), Palacký University Olomouc (LF UP 2024_007), and the SALVAGE project (CZ.02.01.01/00/22_008/0004644). Citation Format: Josef Srovnal,Pavel Stejskal,Alona Rehulkova,Alzbeta Srovnalova,Ondrej Kalita,Marek Slachta,Marian Hajduch. Circulating tumor cells migrate beyond the central nervous system in glioblastoma multiforme [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1991.