Researchers do not know what causes brain tumors. Brain cancer, as with other forms of cancer, occurs when there is an abnormality in cell growth. These abnormalities are caused by mutations or changes within a person’s genes. When the DNA within the genes is abnormal it can result in certain diseases, such as cancer. 

Although there is no single cause for brain tumors, researchers believe there may be some risk factors that increase a person’s chances of developing brain cancer. However, among these factors, very few have been definitively linked to brain cancer. The majority of brain tumors occur without any known cause or related risk factor.  The areas that have been researched for risk factors include environmental factors. Radiation therapy is the only established environmental risk factor for brain tumors. Brain tumors that develop from radiation are due to radiation treatment for another form of head cancer. For most patients with a cancer involving the brain or head, the benefits of receiving radiation therapy outweigh the risk of developing another tumor in the future.

Other environmental factors under investigation include certain chemicals (e.g., vinyl chloride) and electromagnetic fields (such as those generated by cell phones or high-tension wires). However, there has been no definitive evidence linking these elements to brain tumors and the most recent studies indicated no increased risk with cell phone use.

Other potential risk factors for brain tumors include:

• Immune system disorders. Individuals with immune system disorders have an increased risk of developing primary central nervous system lymphomas. The immune system is responsible for protecting the body from cancer and infection. Disorders of the immune system can be present at birth or may develop in patients as the result of treatment for cancer or an organ transplant. An immune system deficiency also may be related to diseases, such as acquired immune deficiency syndrome (AIDS).

  

• Family history and genetics. Some rare cases of brain cancers run in families. Some inherited syndromes have been associated with specific disorders including neurofibromatosis, tuberous sclerosis and Von Hippel-Lindau disease. These conditions are believed to place individuals at higher risk for developing brain or spinal tumors. Some CNS tumors are associated with patterns of altered oncogenes, mutated tumor suppressor genes and chromosomal abnormalities.