Glioblastoma

Synonyms: -

Material:

FFPE tissue sections

TAT:

varies depending on the analysis

Method:

NGS

Overview

Glioblastoma is an adult-type diffuse astrocytic glioma, as classified in the fifth edition of the WHO classification of central nervous system tumours. Glioblastomas are defined as IDH-wildtype and are assigned CNS WHO grade 4 on the basis of histological features, of specific molecular characteristics, or of both. Glioblastoma is the most commonly occurring malignant primary brain and other central nervous system tumour in the United States.

Clinical background and relevance

Molecular characterisation of a diffuse glioma is carried out on tumour material and is relevant both diagnostically and therapeutically. It is required for the diagnosis itself and therefore belongs to the initial diagnostic work-up.

All diffuse gliomas should be tested for IDH1 and IDH2 mutations to meet standard diagnostic requirements. Glioblastoma is by definition IDH-wildtype, so the absence of an IDH1 or IDH2 mutation is a prerequisite for the diagnosis. TERT promoter mutation is one of the molecular alterations that, in an IDH-wildtype diffuse astrocytic glioma, can support a diagnosis of glioblastoma, CNS WHO grade 4. MGMT promoter methylation testing is recommended for all high-grade gliomas (grade 3 and 4) to guide treatment decision making. NTRK1, NTRK2 and NTRK3 are among the genes that form driver fusions in glial, neuronal and glioneuronal tumours. TRK inhibitors may be used for patients with NTRK gene fusion-positive tumours. Deficient MMR (dMMR) or MSI-H status may identify patients for whom tumour-agnostic immune-checkpoint therapy is an option. MSI analysis and MMR-protein immunohistochemistry are complementary approaches and should not be treated as synonymous tests.

Table 1: Clinical relevance of biomarkers in glioblastoma

Biomarker testing	Biomarker finding	Role in the current WHO classification of glioblastoma and clinical relevance
IDH1 and IDH2 sequence analysis	IDH1 and IDH2 wildtype	Prerequisite for the diagnosis of glioblastoma in an adult-type diffuse astrocytic glioma
TERT promoter sequence analysis	TERT promoter mutation present	Molecular characteristics of glioblastoma, IDH-wildtype
MGMT promoter methylation testing	Promoter hypermethylation	Prognostic marker, predictive for response to alkylating and methylating chemotherapy
NTRK1/2/3 fusion testing	NTRK fusion detected	Driver fusion gene, targeted therapy options available for NTRK fusion-positive solid tumours
Microsatellite testing	MSI-H	Treatment options for solid tumours and MMR deficiency available; may indicate the presence of DNA-MMR defect and need for genetic counselling for CMMRDS

Available tests

The single-method analyses listed below can be ordered individually or together as one combined targeted analysis. The assays described here represent a focused set of biomarkers and do not replace comprehensive biomarker profiling when broader testing is clinically indicated.

Single-method analysis	Panel	Gene scope
Sequencing	Panel00701	IDH1, IDH2, TERT
Fusion gene analysis	Panel00698	NTRK1/2/3
MGMT promoter methylation	Panel00699	MGMT
Microsatellite instability (MSI)	Panel00700	Microsatellite marker analysis

Combined analysis	Panel	Gene scope
Targeted analysis	Panel00534	IDH1, IDH2, NTRK1/2/3, MGMT, TERT, Microsatellite marker analysis

Depending on the clinical setting, additional biomarkers not included in the focused panels may be required. These additional analyses on tumour tissue are also available (see Panel 00617 – ).

Therapy

References

Created by

Our editorial team consists of medical specialists and scientists in the field of human genetics. All content is created and reviewed in accordance with current scientific standards.

Last Update : 24.09.2026

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