Table 1 . Intraoperative microdialysis patient characteristics.

Patient ID	Pathology	IDH Status	Other molecular/genetic features	Catheter X	Catheter Y	Catheter Z
Oligo²	Oligodendroglioma WHO 2	Mutant	1p/19q co-deletion; TERT-mutant	NE	NE	NE
Oligo³1	Oligodendroglioma WHO 3	Mutant	1p/19q co-deletion; TERT-mutant	NE	NE	B
Oligo³2	Oligodendroglioma WHO 3	Mutant	1p/19q co-deletion; TERT-mutant	NE	NE	B
Oligo³3	Oligodendroglioma WHO 3	Mutant	1p/19q co-deletion; TERT-mutant	NE	NE	B
GemAstro^3-mut	Gemistocytic Astrocytoma WHO 3	Mutant	None remarkable	NE	NE	B
Astro^4-mut1	Astrocytoma WHO 4 (Recurrent)	Mutant	MGMT non-methylated; loss of CDKN2A/B; complex karyotype	E	NE	B
Astro^4-mut2	Astrocytoma WHO 4	Mutant	MGMT non-methylated; loss of CDKN2A/B	E	NE	B
Astro^4-mut3	Astrocytoma WHO 4 (Recurrent)	Mutant	Indeterminate MGMT methylation	E	E^b	B
H3K27M-Astro^4-WT	Infiltrating Astrocytoma WHO 4	Wild-type	H3K27M, TERT-mutant; MGMT non-methylated	E	NE	B
GBM^WT1	Glioblastoma	Wild-type	MGMT non-methylated; loss of CDKN2A/B; TERT-mutant	E	NE	B
GBM^WT2	Glioblastoma (Primary)	Wild-type	Indeterminate MGMT methylation^a	E	NE	B
GBM^WT2B	Glioblastoma (Recurrent)	Wild-type	Indeterminate MGMT methylation^a	E		B
GBM^WT3	Glioblastoma	Wild-type	MGMT non-methylated	E	NE	B
GBM^WT4	Glioblastoma (Recurrent)	Wild-type	MGMT non-methylated; EGFR amplification; loss of CDKN2A/B	E	NE	B
MolecGBM^WT	Molecular Glioblastoma	Wild-type	Gain of ch. 7, loss of ch. 10; TERT-mutant; MGMT non-methylated	NE	NE	B

E: enhancing tumor; NE: non-enhancing tumor; B: brain adjacent to tumor.
The patient IDs and final pathologic diagnoses, including IDH- status and other available key molecular features, are summarized together with the catheter locations. Additional specifics regarding each patient, tumour, and catheter are available in Supplementary Table 1.
^aDiagnosis of IDH-WT GBM was reached for patient GBM^WT2/2B without need for further molecular studies.
^bRegion of minimal enhancement, suggestive of tumour necrosis.

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