2HG	2-hydroxyglutarate
ALT	alternative lengthening of telomerse
BMBF	Federal Ministry of Education and Research
BP	biological process
C1–C4	consensus classes of LGG with mutual correspondence between expression and methylation: C1- IDH-wt; C2—IDH-A; C3—IDH-O; C4—NL
CC	cell cycle
CL	classical subtype of grade IV gliomas according to Verhaak et al. (2010)
CHOP	CpG-hypomethylation pattern of IDH-mutated tumors
CN	copy number
E1–E8	expression subtypes of LGG
EMT	epithelial–mesenchymal transition
EPL	early progenitor-like subtype
GBM	glioblastoma WHO grade IV
GCIMP	glioma CpG-island hypermethylation phenotype
GCIMP-O	GCIMP with specific hypermethylation of IDH-O
GCIMP-wt	hypermethylation of IDH-wt, particularly of the RTK II type
GEO	gene expression omnibus database
GGN	German Glioma Network
GPCR	G-protein-coupled receptor
GSZ	gene set Z-score
HLA	human leukocyte antigen
HM	hallmarks of cancer
HR	hazard ratio
hx	hypoxia
IDH	isocitrate dehydrogenase
IDH-A	malignant astrocyte-like, IDH-mutated with chromosome 1p19q intact
IDH-mut-codel	IDH mutant additionally carrying co-deletion of chromosome arm 1p and 19q
IDH-mut non-codel	IDH mutant with euploid 1p19q
IDH-O	malignant oligodendrocyte-like, IDH-mutated with chromosome 1p19q intact
IDH-wt	IDH wild-type
LGG	low grade gliomas (WHO grade II and III)
M1–M6	methylation subtypes
ME	mesenchymal subtype of grade IV gliomas according to Verhaak et al. (2010)
MGMT	O-6-methylguanine-DNA methyltransferase
MP	methylation pattern
MS	mesenchymal subtype (Sturm et al. (reanalyzed by Hopp et al.))
NGB	neuroglobin
NL	neural subtype of grade IV gliomas according to Verhaak et al. (2010)
NPC	neural progenitor cells
OS HR	overall survival hazard ratio
Ox	oxidative phosphorylation
PG	pre-glioblastoma subtype of LGG (Gorovets et al., 2012)
PN	proneural subtype of grade IV gliomas according to Verhaak et al. (2010)
PRC2	polycomb repressive complex 2
RTK	receptor tyrosine kinase
RTKI	GBM methylation class (Sturm et al.)
RTKII	GBM methylation class (Sturm et al.)
SOM	self-organizing map
TEL	telomerase
TERT	telomerase reverse transcriptase
TF	transcription factors
TME	tumor microenvironment
TMM	telomere maintenance mechanism