Frequently Asked Questions
What causes brain tumors?
There is only one proven cause of brain tumors in children and adults: ionizing or therapeutic radiation. Most patients have never experienced this type of ionizing or therapeutic radiation prior to their brain tumor diagnosis. Therefore, the cause of brain tumors is unknown in at least 99% of patients.
One rare type of brain tumor, primary brain lymphoma, occurs with a higher frequency in patients who have undergone organ transplants or in patients with AIDS. The development of primary brain lymphoma is associated with the suppression of the immune system.
Around 5% of brain tumors in children and adults arise in part from inherited abnormalities (mutations) in cancer genes. These mutations can occur in oncogenes, which accelerate cancer cell growth, in tumor suppressor genes, which slow down cancer cell growth, or in genome stability genes, which keep the genetic materials (DNA) in order. The single inherited mutation in these genes occurs in all cells in the body and is thought to contribute to, but not to be solely responsible for causing brain tumors.
Inherited diseases that are associated with brain tumors include neurofibromatosis, tuberous sclerosis, retinoblastoma, Li-Fraumeni syndrome, and Von Hippel-Lindau disease.
Many other factors – such as environmental exposures or heredity – have been suggested but not proven. In most cases, patients with a brain tumor have no clear risk factors. The disease is likely the result of several factors acting together.
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What clues to the causes of brain tumors are Duke researchers exploring?
The Preston Robert Tisch Brain Tumor Center has a number of ongoing clinical and laboratory studies to find out what causes brain tumors.
In one project, funded by the Duke Brain Cancer SPORE Grant, investigators from Duke, the Evanston Hospital of Northwestern University, and the University of Illinois at Chicago, are conducting a large epidemiological study to look for specific environmental and genetic risk factors for brain tumors. This study focuses on chemicals that are known to cause brain tumors in animals – animal neuro-carcinogens. Humans may be exposed to these chemicals through their diet and environment, including occupational exposures. Our investigators developed a questionnaire to capture specific dietary and environmental exposures related to animal neuro-carcinogens. Each participant will complete a questionnaire to determine his/her exposure to these chemicals. The exposure information will be linked to the results of analysis of several genes involved in breaking down (metabolizing) chemicals within the body, and repairing damaged DNA. This study is being conducted with a large number of people - both with and without brain tumors – to find specific risk factors that may, or may not, cause brain tumors. For more information about enrollment, please go to Genetic/Environmental Risk and Outcomes for Brain Tumors: Main Study.
In another study, researchers at Duke and Yale Universities are collaborating to find the cause of meningioma, a common and usually benign brain tumor affecting the covering of the brain.
Duke investigators, in collaboration with M.D. Anderson Cancer Center, are also conducting an epidemiological study to find genes that might be responsible for brain tumors occurring in families.
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