Cerebrospinal fluid considerations in glioma

Cerebrospinal fluid (CSF) circulates in the ventricular system and subarachnoid space, and through its interaction with interstitial fluid, facilitates nutrient and waste exchange to support the functional needs of cells in the brain and spinal cord. In the setting of primary brain tumors, CSF has been implicated in tumor pathogenesis by serving as both a reservoir and vehicle for factors which may support tumor progression, therefore contributing to the tumor microenvironment. Pathological manifestations of CSF in the setting of brain tumors include hydrocephalus due to tumor obstruction of CSF pathways, CSF seeding and leptomeningeal metastasis, and transependymal flow. CSF also has roles as a reservoir for biomarkers important in brain tumor detection and as a site for direct delivery of therapeutic agents to bypass the blood brain barrier. Despite the intimate association between CSF and brain tumors, few studies have investigated mechanisms of local and global alterations of fluid flow in the setting of glioma, the most common malignant primary brain tumor in the central nervous system. Here, we provide an overview of recent advances in our understanding of the roles, implications, regulations, and diagnostic/therapeutic implications of CSF in glioma and how they may be leveraged for research and clinical application.