The National Comprehensive Cancer Network (NCCN) updated guidelines to recommend cerebrospinal fluid (CSF)-based molecular tumor profiling for patients with high-grade glioma and glioblastoma when tissue biopsy is not feasible, a change that expands the use of liquid-profiling workflows in neuro-oncology. The NCCN update supports CSF sampling as an adjunctive diagnostic method when direct tissue sampling is impossible due to surgical candidacy or patient refusal, and it also flags CSF tumor-derived DNA in cases where molecular markers drive treatment decisions. The guidance is particularly relevant for molecular subtypes such as H3K27-altered tumors. Belay Diagnostics said the guideline addition supports its Summit 2.0 comprehensive genomic profiling panel, the Ascent chromosomal instability assay, and the Vantage MGMT promoter methylation assay, each designed to be run on a single CSF specimen. The company pointed to earlier analytical and clinical validation work for Summit 2.0.