Variant allelic frequencies of driver mutations can identify gliomas with potentially false-negative MGMT promoter methylation results

Table 1 Patient cohort characteristics

Variable		IDHwt GBM	IDHmut astro	IDHmut oligo
Sex	Male	278	78	49
Sex	Female	170	56	27
Age	median age (range)	64 (33–91)	37 (19–74)	44 (21–78)
Grade	CNS WHO grade 2	N/A	36	38
	CNS WHO grade 3	N/A	55	38
	CNS WHO grade 4	448	43	N/A
Original vs. recurrent	original tumor	391	90	54
Original vs. recurrent	recurrent tumor	57	44	22
MGMT assay	MGMT promoter pyrosequencing assay	291	88	49
MGMT assay	MGMT promoter methylation array	157	46	27
MGMT promoter status	MGMT promoter methylated	172	94	73
MGMT promoter status	MGMT promoter unmethylated	276	40	3
Driver mutation VAF	Mean driver mutation VAF (range)	0.34 (0.02–0.84)	0.38 (0.02–0.79)	0.39 (0.07–0.51)
Driver mutation VAF	Median driver mutation VAF	0.34	0.40	0.40

IDHwt GBM: IDH-wildtype glioblastoma; IDHmut astro: IDH-mutant astrocytoma; IDHmut oligo: IDH-mutant and 1p/19q co-deleted oligodendroglioma

ISSN: 2051-5960