Table 2.

Differing profiles of secondary GB (recurrent vs. radiation induced)

Characteristic	Recurrent secondary GB [6]	Radiation-induced secondary GB
Etiology	Progression from low-grade or intermediate-grade glioma	Development after radiotherapy for other conditions (e.g., leukemia, brain tumor)
IDH mutation	Common (especially IDH1 R132H mutation)	Rare
TP53 mutation	Common	Possible, but less frequent
ATRX inactivation	Common	Possible
MGMT promoter methylation	Common	Possible
TERT promoter mutation	Rare	Possible
1p/19q co-deletion	Rare	Rare
Typical patient age	Usually younger patients	Usually older patients
Medical history	History of low-grade or intermediate-grade glioma	History of radiotherapy for other tumors or diseases
Other chromosomal abnormalities	Common specific chromosomal mutation patterns	May have more heterogeneous chromosomal mutations and structural variations