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When a malignant tumor starts in the brain, it’s referred to as brain cancer, and there are over 120 different types. In the United States, the most common cancer of the brain and central nervous system is glioblastoma. However, the likelihood of a person developing any kind of cancerous brain tumor is less than 1%, which means glioblastoma is quite rare. Recent estimates indicate that about three in 100,000 Americans have glioblastoma.

What causes glioblastoma?

Glioblastoma starts in the brain’s astrocytes, which are cells that provide structure and support for neurons. In fact, glioblastoma is a high-grade form of astrocytoma. Like all cancers, glioblastoma is caused by DNA mutations that result in uncontrolled cell growth.  The underlying causes for these genetic cell mutations are largely unknown.

However, research has revealed that glioblastoma cells have more genetic abnormalities than the cells of other types of astrocytoma brain cancer. Researchers believe that several different genetic mutations are involved in the development of glioblastoma. These genetic mutations can be caused by:

  • Inherited DNA defects
  • Cumulative effects of exposure to certain chemicals and other carcinogens
  • High-dose exposure to ionizing radiation
  • Additional triggers that have yet to be identified

The exact process by which healthy cells become cancerous is not yet completely understood. As with other types of cancerous tumors, glioblastomas form when genetic mutations cause a cell to break away from its normal growth-and-death cycle. One abnormal cell can produce additional copies of itself that can eventually accumulate into a tumor. Glioblastoma cells do not die when they are supposed to; as a result, the tumor can continue to produce new cells and grow into surrounding tissues. Glioblastomas can even produce their own blood vessels to support their rapid growth.

Glioblastoma risk factors

Although the precise cause of glioblastoma hasn’t been clearly defined, researchers have identified a list of characteristics shared by many patients with this form of brain cancer. These characteristics are known as risk factors. While risk factors can be helpful in determining a person’s likelihood of developing glioblastoma, it’s important to remember that:

  • Risk factors do not necessarily cause cancer to develop
  • Many people who have one or more glioblastoma risk factors never develop cancer
  • Some people develop glioblastoma without having any of the known risk factors

Glioblastoma risk factors you can change

So far, studies have not turned up concrete evidence that any lifestyle habits can affect a person’s risk for glioblastoma. Exposure to ionizing radiation therapy—especially to the head or neck—has been identified as a glioblastoma risk factor. Some studies have linked occupational exposure to certain chemicals to an increased risk for brain tumors, but other studies have found no such correlation.

Generally, medical professionals don’t consider glioblastoma to be preventable.

Glioblastoma risk factors you can’t change

Glioblastoma can develop in persons of any age, including children. But it tends to occur more often in adults between the ages of 65 and 74, and men have a slightly higher risk than women.

Most people diagnosed with glioblastoma have no family history of cancerous brain tumors. However, those who have immediate family members with brain tumors have a higher risk of developing the same kind of tumor. One recent study concluded that people whose immediate relatives developed glioblastoma had twice the risk of contracting the same kind of brain cancer compared to people whose immediate family members had never had glioblastoma.

Additionally, people who inherit certain rare genetic syndromes have an elevated risk for glioblastoma. These genetic conditions include:

  • Turcot syndrome
  • Neurofibromatosis type 1
  • Li Fraumeni syndrome
  • Lynch syndrome

Moffitt Cancer Center’s approach to glioblastoma

Moffitt Cancer Center is a nationally ranked cancer hospital offering the full spectrum of cancer care, including genetic counseling and testing, diagnostic services and treatment. The physicians, surgeons, radiologists and other medical practitioners in our Neuro-Oncology Program exclusively treat cancers of the brain and spine. Their vast experience in treating patients with rare forms of cancer, combined with our individualized approach to patient care and our clinical trials program, translates into patient outcomes that are up to four times better than the national average among cancer hospitals.

Moreover, the ongoing clinical research at Moffitt has allowed neuro-oncologists to learn a great deal about how glioblastomas develop and grow. Because we not only treat brain cancers but also emphasize research and innovation, we have been named a Comprehensive Cancer Center by the National Cancer Institute. The more we learn about glioblastoma causes, the closer we get to an eventual cure. 

To learn more about glioblastoma causes and risk factors, schedule a visit with one of our expert oncologists. Call 1-888-663-3488 or submit a new patient registration form online to request an appointment. You do not need a referral to visit Moffitt.

Helpful Links:


American Association of Neurological Surgeons – Glioblastoma Multiforme
American Brain Tumor Association – Glioblastoma (GBM)
American Academy of Neurology – Family History of Brain Tumors Linked to Increased Risk of Brain Cancer
National Organization for Rare Disorders – Glioblastoma