Table 1.

Common genetic and chromosomal aberrations associated with the major glioma subtypes [6]. Abbreviations defined below the table.

Glioma Entity	WHO Grade	IDH1 Mutation	Additional Associated Alterations
Pilocytic astrocytoma	I	Extremely rare	BRAF, KRAS, NF1, FGFR1
Diffuse astrocytoma	II	Common	IDH2, TP53, ATRX, LOH 17p
Anaplastic astrocytoma	III	Common	IDH2, TP53, ATRX, LOH 17p
Oligodendroglioma	II	Majority of cases	IDH2, 1p/19q co-deletion
Anaplastic oligodendroglioma	III	Majority of cases	IDH2, 1p/19q co-deletion
Glioblastoma (primary)	IV	Rare	TERT, PTEN, TP53, MGMT hypermethylation, EGFR, 7+/10−
Glioblastoma (secondary)	IV	Extremely Common	IDH2, TP53, ATRX, LOH 17p

NF1, neurofibromatosis type 1; FGFR1, fibroblast growth receptor 1; IDH2, isocitrate dehydrogenase 2; TP53, tumour suppressor protein 53; ATRX, alpha thalassemia/mental retardation syndrome X-linked mutation; LOH 17p, loss of heterozygosity on chromosome 17; TERT, telomerase reverse transcriptase; PTEN, phosphatase and tensin homolog; MGMT, O(6)-methlyguanine-DNA-methyltransferase; EGFR, epidermal growth factor receptor, 7+/10−, gain of chromosome 7 and loss of chromosome 10. Italics: Genes.