decoding brain tumors with liquid biopsies: a narrative review of a silent sentinel in neuro-oncology

Traditionally, diagnosing brain tumors has relied on tissue biopsies, which are considered the gold standard. however, these invasive procedures come with drawbacks, including the possibility of sampling errors resulting from the heterogeneous nature of tumors. furthermore, they are not ideal for continuous monitoring. in contrast, liquid biopsies offer a promising, minimally invasive alternative by analyzing tumor-derived substances found in biofluids. the goal of this review is to consolidate current research on the role of liquid biopsies in the field of neuro-oncology. specifically, we will explore their applications in diagnosis, tumor classification, treatment monitoring, and the identification of minimal residual disease, while also acknowledging the challenges faced and outlining future directions for this promising technology. essential elements, such as circulating tumor dna, circulating tumor cells, and extracellular vesicles, provide critical genetic and molecular insights. notably, cerebrospinal fluid is often a superior biofluid to blood for brain tumors, as it directly contacts the central nervous system and bypasses the filtering effect of the blood-brain barrier (bbb), yielding higher concentrations of tumor-derived material. liquid biopsies offer several essential advantages, including the ability to capture tumor heterogeneity more effectively and facilitate real-time monitoring of treatment responses. however, their clinical adoption is currently hindered by issues, such as low concentrations of biomarkers in blood, the absence of standardized protocols, and the challenges posed by the bbb. liquid biopsies have the potential to advance personalized care in neuro-oncology significantly. to move these techniques into routine clinical use, future efforts should prioritize technological advancements, the establishment of standardized assays, and the integration of these approaches with artificial intelligence and advanced imaging techniques. this will enhance our ability to tailor treatments more effectively and improve patient outcomes in neuro-oncology.