Molecular pathogenesis of glioblastoma multiforme: Nuances, obstacles, and implications for treatment

Table 1 World Health Organization classification of gliomas

Localized astrocytoma

WHO grade I

Pilocytic astrocytoma

Pleomorphic xanthoastrocytoma

Subependymal giant cell astrocytoma

Diffuse astrocytomas/oligodendrogliomas

WHO grade II (Astrocytoma)

Fibrillary

Protoplasmic

Gemistocytic

WHO grade II (Oligodendroglioma)

WHO grade III (Anaplastic astrocytoma)

WHO grade III (Anaplastic oligodendroglioma)

WHO grade IV (Glioblastoma multiforme)

Giant cell glioblastoma

Gliosarcoma

WHO: World Health Organization.

Table 2 Primary glioblastoma multiforme vs secondary glioblastoma multiforme

	Primary GBM	Secondary GBM
Mean age at diagnosis	Approximately 62 yr of age	Approximately 45 yr of age
Percentage of cases	> 90%	< 10%
Clinical course	Rapid	Smoldering
Origin	De novo	Grade II/III astrocytomas

GBM: Glioblastoma multiforme.

Table 3 Hallmark genetic mutations, primary glioblastoma multiforme vs secondary glioblastoma multiforme

Primary GBM	Secondary GBM
EGFR overexpression/amplification	PDGFR overexpression
Loss of heterozygosity of Ch. 10q	Loss of heterozygosity of Ch. 10q
PTEN deletion on Ch. 10	p53 mutations
p16 deletion	p16/Rb pathway aberrancies

GBM: Glioblastoma multiforme; EGFR: Epidermal growth factor receptor; PDGFR: Platelet-derived growth factor receptor; PTEN: Phosphatase and tensin homolog.