Summary
Tumour type | Genetic marker | Description | Known imaging features |
Astrocytoma, IDH mutant | IDH1, IDH2 (isocitrate dehydrogenase 1 and 2) | Enzymes in Krebs cycle, involved in isocitrate to alphaketoglutarate reaction and NADPH production | Relatively circumscribed homogenous high T2w signal supratentorial lesions most commonly seen in the frontal or temporal lobes |
ㅤ | ATRX (alpha thalassemia retardation syndrome X-linked) | Regulates cell cycle and telomere length. Modulates p53 in cancer | T2-FLAIR mismatch with FLAIR hyperintense rim |
ㅤ | TP53 (tumour protein p53) | Tumour suppression gene that regulates cell cycle | Grade 2 typically non-enhancing however higher lesions can show enhancement and appear more heterogeneous |
ㅤ | CDKN2A/B (cyclin-dependent kinase inhibitors) | Genes located on chromosome 9 which code for tumour suppressor genes p14, p15, and p16 | ㅤ |
Oligodendroglioma, IDH-mutant and 1p/19q-codeleted | IDH1, IDH2 | Enzymes in Krebs cycle, involved in isocitrate to alphaketoglutarate reaction and NADPH production | Supratentorial lesions with a frontal lobe predilection and infiltrative margins |
ㅤ | 1p/19q | Occur as combined deletion of entire chromosome arms 1p/19q after unbalanced translocation between chromosomes 1 and 19 [t(1:19)(q10;p10)] | Heterogenous with calcification typically present T2/FLAIR mismatch sign not a feature |
ㅤ | TERT promoter | Gene located on chromosome 5p15.33 and encodes for the catalytic subunit of telomerase | Varying degrees of enhancement which does not correlate well with tumour grade |
ㅤ | NOTCH1 | Encodes a transmembrane protein that functions in multiple developmental processes and the interactions between adjacent cells | ㅤ |
Glioblastoma, IDH-wildtype | IDH-wildtype (isocitrate dehydrogenase 1 and 2) | Enzyme in Krebs cycle, involved in isocitrate to alphaketoglutarate reaction and NADPH production | Heterogenous T2w hyperintense mass with enhancement and restricted diffusion within the solid components with extensive perilesional signal abnormality |
ㅤ | TERT promoter | Gene located on chromosome 5p15.33 and encodes for the catalytic subunit of telomerase | Multiple areas of susceptibility artefact in keeping with intralesional haemorrhage |
ㅤ | Chromosomes 7/10 | \u002B7/-10 chromosome copy number changes | Note, molecularly defined glioblastomas may lack necrosis or parenchymal enhancement on magnetic resonance imaging (MRI) |
ㅤ | EGFR (epidermal growth factor receptor) | Oncogene encoding a tyrosine kinase resulting in increased DNA synthesis | ㅤ |
Genetic features
Molecular marker | Clinical significance |
ATRX mutation Alpha-thalassemia/mental retardation syndrome X | - Common in astrocytoma, IDH-mutant (not in oligodendroglioma) and diffuse hemispheric glioma, H3 G34–mutant |
BRAF V600 mutation | - Frequently present in pleomorphic xanthoastrocytoma, also in ganglioglioma and epithelioid glioblastoma |
CDKN2A/B homozygous deletion Cyclin-dependent kinase inhibitor 2A/B | - Present in astrocytoma, IDH-mutant indicates poor prognosis |
EGFR gene amplification Epidermal growth factor receptor | - Common in glioblastoma, IDH-wildtype CNS WHO grade 4 - If present in astrocytoma, IDH-wildtype CNS WHO grades 2 or 3, it is consistent with glioblastoma, IDH-wildtype CNS WHO grade 4 |
EGFR-mutations | - Most common is EGFRvIII, frequently present in glioblastoma, IDH-wildtype CNS WHO grade 4 |
H3 G34 mutation Histone H3 3 G34 | - Present in hemispheric diffuse glioma, IDH-wildtype, predominantly in children and young adults, poor prognosis |
H3 K27M mutation Histone H3 K27M | - One of the criteria of diffuse midline glioma, H3 K27M altered - May occur in other gliomas not located in the midline (pilocytic astrocytoma and ependymoma) |
IDH1/2 Isocitrate dehydrogenase | - Frequently mutated in diffuse gliomas (astrocytomas and oligodendrogliomas) and is associated with better prognosis than IDH-wildtype gliomas |
KIAA1549-BRAF gene fusion | - Frequently found in pilocytic astrocytoma, also in diffuse leptomeningeal glioneuronal tumour, pilomyxoid astrocytoma and ganglioglioma |
MAPK Mitogen-activated protein kinase pathway | - Alterations typical for paediatric-type diffuse low-grade gliomas |
MGMT promotor methylation O6-methylguanine DNA methyltransferase | - DNA repair enzyme, methylation predicts good response to alkylating agents such as temozolomide in glioblastoma, IDH-wildtype |
MYB- or MYBL1-altered | - Alterations typical for a paediatric low-grade glioma |
TERTp mutation Telomerase reverse transcriptase promotor | - Present in most oligodendroglioma - If present in diffuse astrocytoma, IDH-wildtype CNS WHO grades 2 and 3 (i.e. without the histopathological hallmarks of glioblastoma (necrosis and/or microvascular proliferation)), it is consistent with glioblastoma IDH-wildtype CNS WHO grade 4 |
TP53 mutation | - Present in most astrocytoma IDH-mutant, rare in oligodendrogliomas |
YAP1 fusions Yes-associated protein 1 | - Present in some supratentorial ependymomas, especially in paediatric tumours |
ZFTA fusions Zinc finger translocation associated | - Present in some supratentorial ependymomas (ZFTA: previously named RELA fusions) |
Gain of chromosome 7/loss of chromosome 10 (+7/−10) | - Common in glioblastoma IDH-wildtype CNS WHO grade 4 |
Loss of chromosome 1p and 19q (loss of heterozygosity) (1p/19q codeletion) | - Prerequisite for the diagnosis of oligodendroglioma |
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