Category: Samples and data management
Labels: samples tests, inclusion criteria
Creation date and Author: Merry K., July 31st 2025
Last Update and Author: Astrid C., September 2nd 2025
Related questions:
- Why are we conducting DNA methylation profiling on GBM samples?
- Process for GBM patients validation
- What if the IDH status of the patient is not validated?
DNA methylation profiling Rationale
Traditional histopathological methods for diagnosing GBM often face challenges due to the tumor's heterogeneity and overlap with other brain malignancies.
Methylome profiling provides a molecular "barcode" unique to each tumor type, enabling more accurate classification and resolution of diagnostic ambiguities, especially in cases where histology is inconclusive or mismatched with molecular features.
This refinement is particularly useful for identifying subtypes of GBM, such as IDH-wildtype or methylation-based subclasses, which have distinct prognostic and therapeutic implications.
In the ROSALIND study, only GBM IDH-wt patients are included.
Q&A
What is the process for GBM patients validation?
IDH1 testing by IHC at participating center (financed by CURE51) and shipment of IDH1-wt (and IDH2 unknown) samples OR shipment of the unknown IDH samples and testing at CURE51 lab.
Histological review by experts and exclusion of patients known not to be GBM and with insufficient QC control.
Methylome profiling and characterization by an expert.
Sequencing (WES) and final validation of IDH2.
Which tests are funded by CURE51 to validate the IDH status?
- IDH1 testing by IHC is required. Costs are covered by Cure51 in cases where the IDH1 status is unknown. If IDH1 testing cannot be performed at the site, it will be conducted at CURE51 central laboratory.
- Any previously generated and relevant molecular information—such as EGFR, ATRX, or TP53 status—is shared, if available.
- At Cure51, methylation profiling is conducted, from which IDH2 status can be inferred if necessary.
- An initial assessment of necrosis and tumor cellularity, performed through histological review at the central laboratory, will allow for prioritization of the samples. Methylome profiling will then confirm the glioblastoma diagnosis according to the latest WHO classification, in collaboration with our lead pathologist.