Patient Faqs
What is Whole-Genome DNA Methylation Profiling?
Whole-Genome DNA Methylation Profiling is an advanced genomic test that examines patterns of DNA methylation at hundreds of thousands of locations across a tumor’s DNA.
Different types of brain tumors have characteristic methylation patterns. These patterns can serve as a molecular fingerprint that helps identify what type of tumor a patient has.
Gliolab performs Whole-Genome DNA Methylation Profiling using the Epignostix Classifier, which compares the tumor’s methylation pattern with established reference profiles of central nervous system tumors.
Why should a patient with glioblastoma consider DNA methylation profiling?
Every glioblastoma patient deserves the most precise diagnosis possible.
Brain tumors that look similar under the microscope can have different molecular characteristics. DNA methylation profiling provides another level of information by examining the tumor’s molecular pattern.
The test can help confirm or refine a patient’s diagnosis and also provide important additional information about the tumor, including MGMT promoter methylation, molecular class and subclass, and copy-number changes in genes relevant to brain tumors. This information can help your physician better understand your tumor and can help guide treatment.
How can DNA methylation profiling help confirm or refine my diagnosis?
Traditionally, brain tumors have been diagnosed by examining tumor tissue under a microscope. Today, molecular information plays an increasingly important role in accurately classifying brain tumors.
A tumor’s DNA methylation pattern acts somewhat like a molecular fingerprint. At Gliolab, we compare your tumor’s methylation pattern with established reference profiles of different central nervous system tumors.
A strong match can provide additional molecular support for a diagnosis of glioblastoma. In some cases, methylation profiling may refine the diagnosis or identify a different type of brain tumor that can look similar under the microscope.
Your physician interprets the methylation results together with the pathology findings and other clinical and molecular information.
What information will the test provide about my tumor?
Whole-Genome DNA Methylation Profiling can help confirm or refine a glioblastoma diagnosis, guiding treatment decisions.
- A Molecular classification of the tumor, including class and subclass when applicable
- A classifier score indicating the strength of the molecular classification
- MGMT promoter methylation probability
- Copy-number changes involving 29 genes relevant to central nervous system tumors
- Characteristic chromosome changes, including chromosome 7 gain and chromosome 10 loss
Together, these results provide a more detailed molecular picture of your tumor that your physician can interpret along with your other clinical and pathology findings.
What is MGMT promoter methylation and why is it important for treatment?
MGMT is a gene that helps cells repair damaged DNA.
When the promoter region of the MGMT gene is methylated, tumor cells may produce less MGMT protein. This can make glioblastoma cells more sensitive to DNA damage caused by temozolomide, a chemotherapy drug commonly used to treat glioblastoma.
For this reason, MGMT promoter methylation is an important biomarker that physicians consider when making treatment decisions for patients with glioblastoma.
Gliolab’s test provides an MGMT promoter methylation probability as part of the methylation analysis.
Will this test help my doctor make treatment decisions?
The primary purpose of Whole-Genome DNA Methylation Profiling is to help establish or refine the molecular diagnosis and provide a more detailed characterization of the tumor.
Some of the information can also be relevant to treatment. For example, MGMT promoter methylation is an important biomarker when physicians consider treatment with temozolomide.
Molecular class, subclass, and copy-number findings provide additional information about the biology of the tumor and may also be relevant when considering clinical trials and treatment approaches.
Your physician will interpret the results together with your pathology, imaging, other molecular tests, overall health, and available treatment options.
Can my existing tumor tissue be used, and how much tissue is needed?
Yes. In most cases, existing formalin-fixed, paraffin-embedded (FFPE) tumor tissue from your surgery or biopsy can be used, so another procedure is generally not needed just for this test.
Your physician or pathology laboratory can arrange for the appropriate tumor sample to be sent to Gliolab.
How does my doctor order the test, and how long will results take?
Whole-Genome DNA Methylation Profiling must be ordered by a physician or other authorized healthcare provider.
Your provider can request an account through the Order a Test section of the Gliolab website. After the account is approved, the provider completes the Test Requisition Form and submits it through Gliolab’s secure LabLink portal. Your tumor specimen is then sent to Gliolab for testing.
The expected turnaround time is approximately 7–14 business days after an acceptable specimen is received.
Once testing is complete, the clinical report is made available securely to the healthcare provider who ordered the test. Your physician can then discuss the results with you and explain what they mean for your diagnosis and care.
Will insurance cover the test, and is testing available to me?
Our Whole-Genome DNA Methylation test is covered by Medicare.
Gliolab is committed to providing testing to glioblastoma patients regardless of insurance status. If you have questions about insurance, billing, or financial assistance, please contact Gliolab.
At this time, Gliolab is not accepting specimens originating from California, New York, Maryland, or Pennsylvania due to state laboratory licensing requirements. Gliolab is working to expand testing availability in these states.
