Fig. 4.

CSF-ctDNA provides robust detection of tumor-specific alterations for brainstem tumors as compared to plasma ctDNA. a For eight cases with available primary tumor tissue DNA, both the CSF ctDNA and plasma ctDNA were isolated and sequenced by NGS for genes frequently mutated in brain tumors. b CSF identified the majority of alterations in the primary tumor, but also identified additional alterations undetected in the tumor. c Positive detection rates were higher for CSF ctDNA as compared to plasma ctDNA, as were the d, e mutant allele fractions of the variants identified