NCCN updated its guidelines to recommend CSF-based molecular tumor profiling for patients with high-grade glioma or glioblastoma when tissue biopsy is not feasible. The update supports use of cerebrospinal fluid specimens obtained via lumbar puncture as an adjunctive diagnostic approach. Belay Diagnostics said the change includes its Summit 2.0 comprehensive genomic profiling panel, Ascent chromosomal instability assay, and Vantage MGMT promoter methylation assay. The company noted that each test can be run on a single CSF specimen. The guideline update adds inoperable HGG and GBM to a growing set of CNS cancers for which CSF-based testing is recommended when tissue sampling is difficult or impossible.