Table 2.

Histopathological Features of Adult H3 K27M-Mutant DMG

Presence of necrosis and/or microvascular proliferation
Absent	22/58 (38%)
Present	36/58 (62%)
Not reported	2
Immunohistochemical testing
H3 K27M mutation	59/59 (100%)
H3 K27 trimethylation complete loss	15/16 (94%)
H3 K27 trimethylation mosaicism	1/16 (6%)
IDH1 R132H mutation	0/55 (0%)
p53 expression >10%	32/47 (68%)
ATRX loss	21/55 (38%)
BRAF V600E mutation	0/20 (0%)
Molecular analysis
MGMT promoter methylation	2/22 (9%)
EGFR amplification (FISH)	0/25 (0%)

Summary table for histologic features, immunohistochemical stains, MGMT promoter analysis, and EGFR amplification status of tumors.

Denominator indicates the number of patients tested.