Fig. 3.

Sequencing of CSF-derived ctDNA accurately detects tumor-specific alterations found in the primary tumor tissue (N = 47). a Using parallel sequencing of the primary tumor DNA as well as CSF-derived ctDNA, tumor-specific alterations were identified and compared to one another. b, c The majority of cases show a high level of consistency between the tissue DNA detected variants and those identified in the CSF ctDNA. d In 17.0% of cases overall, mutations were detected in the CSF ctDNA that were undetectable in the primary tumor. In half of these cases, the primary tumor had undetectable mutations from the tissue specimen