What Causes Brain and Spinal Cord Tumors in Adults?

The cause of most brain and spinal cord tumors is not fully understood, and there are very few well-established risk factors. But researchers have found some of the changes that occur in normal brain cells that may lead them to form brain tumors.

Normal human cells grow and function based mainly on the information contained in each cell’s DNA. Brain and spinal cord tumors, like other tumors, are caused by changes in the DNA inside cells. DNA is the chemical that makes up our genes, which control how our cells function. We usually look like our parents because they are the source of our DNA. But DNA affects more than how we look.

Some genes control when our cells grow, divide into new cells, and die:

  • Certain genes that help cells grow, divide, and stay alive are called oncogenes.
  • Genes that help keep cell division under control, or make cells die at the right time, are called tumor suppressor genes.

Cancers can be caused by DNA changes that turn on oncogenes or turn off tumor suppressor genes. These gene changes can be inherited from a parent, but more often they happen during a person’s lifetime.

Inherited gene changes

Researchers have found gene changes that cause some rare inherited syndromes (like neurofibromatosis, tuberous sclerosis, Li-Fraumeni syndrome, and von Hippel-Lindau syndrome) and increase the risk of developing some brain and spinal cord tumors. For example, the Li-Fraumeni syndrome is caused by changes in the TP53 tumor suppressor gene. Normally, this gene prevents cells with damaged DNA from growing. Changes in this gene increase the risk of developing brain tumors (particularly gliomas), as well as some other cancers.

Gene changes acquired during a person's lifetime

Most often, it's not known why people without inherited syndromes develop brain or spinal cord tumors. Most exposures that cause cancer somehow damage DNA. For example, tobacco smoke is a risk factor for lung cancer and several other cancers because it contains chemicals that can damage the genes inside cells. The brain is relatively protected from tobacco smoke and other cancer-causing chemicals that we might breathe in or eat, so these factors are not likely to play a major role in these cancers.

Several different gene changes usually occur in normal cells before they become cancerous. There are many kinds of brain tumors, each of which may have different sets of gene changes. A number of gene changes have been found in different brain tumor types, but there are probably many others that have not yet been found.

Researchers now understand some of the gene changes that occur in different types of brain tumors, but it’s still not clear what causes most of these changes. Some gene changes might be inherited, but most brain and spinal cord tumors are not the result of known inherited syndromes. Other than radiation, no known lifestyle-related or environmental factors are clearly linked to brain tumors. Most gene changes are probably just random events that sometimes happen inside a cell, without having an outside cause.

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Chang SM, Mehta MP, Vogelbaum MA, Taylor MD, Ahluwalia MS. Chapter 97: Neoplasms of the central nervous system. In: DeVita VT, Lawrence TS, Rosenberg SA, eds. DeVita, Hellman, and Rosenberg’s Cancer: Principles and Practice of Oncology. 10th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2015.

Dorsey JF, Hollander AB, Alonso-Basanta M, et al. Chapter 66: Cancer of the central nervous system. In: Abeloff MD, Armitage JO, Niederhuber JE. Kastan MB, McKenna WG, eds. Abeloff’s Clinical Oncology. 5th ed. Philadelphia, Pa: Elsevier; 2014.

Last Medical Review: September 30, 2017 Last Revised: November 6, 2017

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