Glioma Specialty Group Overview

Kay Pool: I've been skating since I was five. One of my favorite things to do is to bring the kids and be able to have them involved in that, too. My first symptoms, I had two grand mal seizures. We have a young family, we were expecting a baby. Then in December I had a major focal seizure. I couldn't speak at all.

Daniel Lachance, M.D.: Ms. Pool came to Mayo Clinic after having some epileptic seizures and those seizures led to imaging studies of the brain, and we shortly learned that she had a glioma, which is a type of primary tumor of the brain.

Ian Parney, M.D.: One of the things, though, that was very unique about her case was that when this happened, she was expecting. She was 21 weeks pregnant. The best treatment for baby is the best treatment for mom in these situations, so we wanted to go ahead and think about surgery for her. That was a complex thing.

Kay Pool: We had already talked to Dr. Lachance, so we knew what they had suggested, which was to have the awake brain surgery. And we talked to Dr. Parney. He was very specific about what was going to happen, so we didn't have to wonder.

Byron Pool: You know, it's not an operation that happens every day. And she was confident, he was confident. And because of where the tumor was and the fact that it affected her speech, that was kind of our only option.

Ian Parney, M.D.: I can't overemphasize how important it is to have experience in managing things as brain tumors. Here at Mayo Clinic, we perform over 1,000 brain tumor procedures per year just in Rochester alone.

Byron Pool: We really like the fact that they weren't afraid to ask other doctors questions either. We felt like we had a real team working for us.

Ian Parney, M.D.: We had folks from neurology, from neuro-oncology, from neurosurgery.

Daniel Lachance, M.D.: And then a high-risk obstetrics team to help manage the pregnancy.

Ian Parney, M.D.: Everybody just brings a wealth of experience, which really translates to better outcomes.

Kay Pool: We just felt like everyone felt confident about this being the best choice for us.

Ian Parney, M.D.: She came through the surgery very well, without any major neurological problems. One of the really cool things for me was at the end of the procedure we had the ultrasound of the baby, and I swear the baby waved at me. It was really an exciting thing.

Kay Pool: I'm really thankful that I get to be a mom to two great kids. Really enjoying that time day to day has been wonderful.

People with gliomas who receive care in the Mayo Clinic Brain Tumor Program are treated by internationally respected doctors who specialize in this type of brain tumor. Mayo doctors use advanced diagnostic technologies and innovative treatment approaches to develop a care plan tailored to each situation.

Innovation in diagnosis and treatment

People with gliomas may benefit from the molecular diagnostics and classification capabilities of Mayo Clinic. An accurate diagnosis is critical to deciding on the right treatment. Once you start down a treatment path, it may not be possible to change therapies.

Our physician-scientists were instrumental in developing a new classification system for glioma. That means your doctors are able to make accurate diagnoses and recommend appropriate treatments from the start.

Our brain tumor team helps many people referred by their doctors from local clinics to access expertise for rarely seen or complex situations. For example, Mayo Clinic has treated women with glioma during their pregnancies. And the clinic's radiology specialists can perform MRI scans on people with implanted medical devices such as pacemakers.

Each person's treatment plan may vary significantly depending on the size and location of the tumor, symptoms, tumor genetics, and personal goals. Options include surgery, radiation therapy, chemotherapy, targeted drug therapy and treatment innovations.

Molecular classification of brain tumors


Unlocking the Power of Gene Expression: Molecular classification of brain tumors

Joon H. Uhm, M.D., Neurology, Mayo Clinic: Molecular testing or DNA testing on tumors -- now, in the 21st century -- needs to be considered for the great majority, if not all, brain tumor patients.

Robert B. Jenkins, M.D., Ph.D., Laboratory Medicine and Pathology, Mayo Clinic: We need to use molecular genetic tools to help improve the classification of gliomas, to determine a patient's prognosis, and to determine the kind of therapy that they should receive.

Daniel Honore Lachance, M.D., Neurology, Mayo Clinic: Brain tumors actually occur as a result of a large number of genetic alterations.

Dr. Uhm: What the researchers here at Mayo Clinic and across other institutions have found is that looking at the DNA, you can classify brain tumors far more precisely than simply by looking how pink they are, how the cells are dividing.

Dr. Jenkins: We can use, though, that genetic information to more solidly place these tumors into specific types that might respond to specific kinds of therapy.

Ian F. Parney, M.D., Ph.D., Neurologic Surgery, Mayo Clinic: Patients with certain molecular classifications that do really well with one treatment but not with another. And as we now have this established as a way that we can look at this information, we're really going to be able to tailor our treatments much better and find new treatments better for patients that may be underserved by what we had before.

Dr. Jenkins: We discovered that the short arms of chromosome one and the long arm of chromosome 19 were co-deleted in a particular kind of glioma.

Dr. Uhm: What we call 1p/19q deletion. This is when two pieces of DNA in the human chromosomes, basically, disappear. And we don't really know why that's a good thing for the patient, but when those two pieces of DNA are missing, that patient's brain tumor is actually forecasted to grow a bit more slowly but very importantly, be more sensitive to radiation and to certain categories of chemotherapy.

Dr. Jenkins: Some brain tumors have 1p/19q co-deletion. Some brain tumors have IDH mutation. Some brain tumors have TERT promoter mutation. Some tumors have all three of those. Some tumors have none of those. Some tumors have one or two of those. So we thought, well if we can test the tumors for those three alterations, we could put them into molecular genetic groups.

Dr. Lachance: By just using three key genetic mutations, gliomas could be classified into five groups that have in common certain important characteristics such as the age of presentation.

Dr. Jenkins: Those five molecular groups can predict the patient's prognosis, meaning how long they can expect to live, and at least two of the groups determine what kind of therapy the patient will get. So for example, a person that has what we called a triple-positive glioma -- meaning they have 1p/19q co-deletion, IDH mutation, and TERT promoter mutation -- those patients should be getting chemotherapy and radiation therapy regimen specifically designed for that tumor and that tumor type only.

Dr. Uhm: If a person's tumor is missing 1p19q, there's no doubt that we should give that patient chemotherapy, either with or after the radiation, and that actually doubles the life expectancy with radiation alone from about eight years to about 15, 16 years, or more.

Dr. Lachance: The patient that has the combination, say of all three mutations -- the co-deletion, IDH mutation, and the TERT promoter mutation -- we know that those patients have, in oncology speak, median survivals of greater than 15 years and with some patients that are truly long-term survivors. If we treated those patients too aggressively at the onset, when they live 15 to 20 years, they may suffer the long-term consequences of our therapies and be neurologically impaired because of the treatments. When, if perhaps, we could come up with a different approach for those patients that we know are going to do well, they might end up having a better longer term quality of life.

Dr. Uhm: IDH mutation and telomerase mutation and they also have a very good prognosis. The next one down is IDH mutation only and then you have what's called triple negative. And when you have none of these three good genetic characteristics, that patient -- it's not a guarantee that he or she would do poorly -- but it doesn't look well.

Dr. Jenkins: If they have one of the mutations, meaning if they have a TERT promoter mutation, that group of tumors is what we used to call primary glioblastoma. The most common brain tumor and the tumor of the worst prognosis. If a tumor falls into that group, they get a different chemotherapy and a different radiation therapy.

Dr. Parney: We're able to use the molecular findings to help augment the information that we get from the MRI scans to get the best surgical approach for an individual patient. If that particular tumor has an IDH mutation, then there is a very strong association with improved survival and outcome if we take out all of the area that we can safely take out. So what we always want to do in any brain tumor surgery is that we want to take out the most tumor that we can safely take out to get the best outcome and survival.

Dr. Lachance: Each person's tumor is different and therefore, in the end, each person needs an individualized approach to treating their tumor. And it's only by having this kind of detailed information available that we can begin to understand the different patterns of patients' different tumor types.

Dr. Uhm: We now have five molecular categories of glioma. We're absolutely certain it goes far beyond five. It'll be 50, 500, who knows. There are thus far 40,000 known human genes. 40,000. And we now five types of human brain tumors based upon genetics. So really, I think the sky's the limit.


Your treatment team

Your treatment team may include a neurosurgeon, a neuroradiologist, a radiation oncologist, a neuro-oncologist and others as needed. Together they work with you to develop an individualized treatment plan. Complex conditions are reviewed by a large, multidisciplinary tumor board. You receive comprehensive care for the diagnosis and treatment of your condition, with access to in-depth counseling, unbiased review of all available treatment options, follow-up care and rehabilitation.

Clinical trials

Mayo Clinic is top-ranked in more specialties than any other hospital and has been recognized as an Honor Roll member according to the U.S. News & World Report's 2024-2025 "Best Hospitals" rankings.

Mayo Clinic in Rochester, Minnesota, Mayo Clinic in Phoenix/Scottsdale, Arizona, and Mayo Clinic in Jacksonville, Florida, rank among the Best Hospitals for neurology and neurosurgery in the U.S. News & World Report Best Hospitals rankings. Mayo Clinic Children's Center in Rochester is ranked the No. 1 hospital in Minnesota, and the five-state region of Iowa, Minnesota, North Dakota, South Dakota and Wisconsin, according to U.S. News & World Report's 2023-2024 "Best Children's Hospitals" rankings.

See physician staff



  • Mayo Clinic Brain Glioma Specialty Group
  • Neurosurgery
  • 5779 E. Mayo Blvd.
    Phoenix, AZ 85054


  • Mayo Clinic Brain Glioma Specialty Group
  • Neurology and Neurosurgery
  • 4500 San Pablo Road
    Jacksonville, FL 32224


  • Mayo Clinic Brain Glioma Specialty Group
  • Adult Neurology and Neurosurgery
  • 200 First St. SW
    Floor 8
    Rochester, MN 55905
June 15, 2024