The role of exosomes in brain tumors: Mechanisms, diagnosis, and therapeutic prospects.

Cancer remains a leading cause of mortality worldwide, with metastases significantly impacting patient prognosis. Brain metastases (BM) and primary malignant gliomas, such as glioblastoma (GBM), are among the most aggressive forms, with survival rates often below 12 months. GBM alone accounts for 2.5% of cancer-related deaths globally and is a leading cause of mortality in young adults aged 15-34. One of the major challenges in treating brain tumors is the blood-brain barrier (BBB), which limits the delivery of therapeutic agents to the central nervous system (CNS). Exosomes, a subset of extracellular vesicles (EVs), have emerged as promising candidates for overcoming these challenges due to their natural ability to transport bioactive molecules across biological barriers. These nanosized vesicles (30-150 nm) are actively involved in tumor progression, angiogenesis, immune modulation, and drug resistance. Recent studies have highlighted their potential as biomarkers for early cancer detection and as drug delivery vehicles capable of crossing the BBB. Despite their promise, challenges such as large-scale production, efficient cargo loading, and targeted delivery remain critical hurdles to clinical translation. This review explores the role of exosomes in brain malignancies, focusing on their involvement in tumor progression, potential utility as diagnostic biomarkers, and prospective therapeutic applications.