The Role of Genetic Profiling in Glioma Treatment
- Moving beyond what tumor cells look like under a microscope, doctors now use genetic “fingerprints” to diagnose glioma and better predict how a tumor will behave and which treatments might work best.
- Determining if a patient’s tumor has an IDH mutation is particularly important, as this can significantly shape your treatment plan and outlook. IDH-mutant tumors often respond better to therapy.
- Armed with a detailed molecular profile, your medical team can tailor therapies just for you, offering more precision and potentially better outcomes in the fight against glioma.
Historically, gliomas were classified mainly by what doctors saw under a microscope: how the tumor cells were shaped, how quickly they grew, and how the tissue looked compared to healthy brain cells. While this remains important, doctors now consider the tumor’s genetic traits a crucial key to providing effective treatment as well.
Read MoreUnderstanding IDH: The Game-Changing Mutation
One of the most critical pieces of the molecular puzzle is the IDH (isocitrate dehydrogenase) gene. Gliomas are generally split into two main groups based on IDH status:
IDH-Mutant Gliomas
- Tend to occur in younger patients
- Often have a better prognosis and respond well to treatment
- Classified as WHO grade 2, 3, or 4—yet even within the higher grades, the mutant status often signals a more controlled course
IDH-Wild Type Gliomas
- Often more aggressive, with a higher tendency to behave like glioblastomas (WHO grade 4)
- Usually found in older patients
- Typically require intensive treatment strategies
Identifying your tumor’s IDH status is a crucial first step in deciding what comes next for your care.
This classification is a must when evaluating newly diagnosed patients with glioma because it supports and guides the tumor’s grading, which is closely related to the aggressiveness of the cancer.
Going Beyond IDH: Other Molecular Markers
While the IDH mutation is a key indicator for doctors, it’s not the only factor that helps guide treatment. Your medical team may look for other genetic “flags” in your tumor’s DNA. Each one can provide valuable clues about how aggressive the tumor might be and which treatments could fit best. Some of these “flags” are listed below and might help your understanding of your results and facilitate discussion with your healthcare provider:
- 1p/19q Co-Deletion: This means parts of two specific chromosomes — called 1p and 19q — are missing in the tumor cells. This genetic change is commonly found in a type of glioma called oligodendroglioma. Patients with a 1p/19q co-deletion often respond better to treatments like radiation and certain chemotherapies and usually have a more favorable overall outlook.
- MGMT Promoter Methylation: MGMT is a gene that helps cells fix damaged DNA. When the “promoter” region of this gene is methylated, it means the gene is less active — or even shut off. If MGMT is “turned off,” the tumor cells can’t repair themselves as easily after chemotherapy. That means certain chemo drugs could be more effective against tumors that have MGMT promoter methylation.
- TERT Promoter Mutations: TERT stands for “telomerase reverse transcriptase.” This enzyme helps cells keep their DNA healthy enough to keep dividing. A TERT promoter mutation can change how this enzyme works. TERT mutations often appear in more aggressive gliomas (like glioblastomas). Knowing whether your tumor has this mutation helps your doctor predict how fast the cancer may grow and can guide treatment choices.
“Routinely now, we get all of those things tested for all of our glioma patients’ tumors to give the full evaluation of where it is,” Dr. Newton explains. “… We have a lot of things we have to do now to truly classify it the right way, and the things that make the most difference are really these molecular markers.”
By piecing together a tumor’s entire molecular profile, doctors gain a holistic view of its behavior and can choose treatments — from surgery and radiation therapy to targeted drugs — most likely to work for you.
Questions To Ask Your Doctor
- How do my tumor’s genetic markers affect my prognosis?
- Are there any clinical trials I might be eligible for based on these markers?
- How often will we need to monitor my tumor’s genetic markers?
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