Table 4.

Grade and age distribution of IDH1-negative gliomas.

Tumor grade	N	Percent	Median age (years)
Diffuse astrocytoma grade II NOS	2	6.7	42
Anaplastic astrocytoma grade III NOS	2	6.7	23
Glioblastoma grade IV	26	86.6	56
	30	100.0