Circulating Tumor Cells in Glioblastoma

Glioblastoma multiforme (GBM) remains a devastating brain tumor with poor prognosis, traditionally viewed as non-metastatic. The recent detection of circulating tumor cells (CTCs) in glioblastoma challenges this long-held view and opens new opportunities for liquid biopsy in neuro-oncology. This review summarizes current understanding of glioblastoma CTCs, emphasizing their unique properties, detection technologies, and differences compared to CTCs in extracranial cancers. Key challenges include their rarity, the absence of epithelial markers, and the presence of the blood–brain barrier. Despite the need for specialized enrichment approaches, CTC analysis in glioblastoma can offer helpful information regarding tumor heterogeneity, treatment response, and minimal residual disease. We discuss emerging clinical studies leveraging CTCs for early relapse detection and therapy monitoring. Integrating CTC phenotyping with molecular and functional characterization may enhance future personalized treatment strategies in glioblastoma. Refined CTC methodologies combined with other liquid biopsy modalities may transform glioblastoma management, improving patient outcomes through less invasive, dynamic tumor surveillance.