What Causes Brain and Spinal Cord Tumors in Children?

The cause of most brain and spinal cord tumors is not fully understood, and there are very few known risk factors for these tumors. But researchers have found some of the changes that occur in normal brain cells that may lead them to form 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 usually caused by changes (mutations) 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 cause cells to 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 (as is sometimes the case with childhood cancers), but more often they are acquired during a person’s lifetime.

Inherited gene changes

Researchers have found the gene changes that cause some rare inherited syndromes (like neurofibromatosis, tuberous sclerosis, Li-Fraumeni syndrome, and von Hippel-Lindau disease) 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.

Acquired gene changes

Most often, it's not known why children without inherited syndromes develop brain or spinal cord tumors. Most exposures that cause cancer, such as tobacco smoke, somehow damage DNA. But the brain is relatively protected from most cancer-causing chemicals that we might breathe in or eat. What’s more, children are less likely to have been exposed to many of these chemicals.

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 these changes. Some gene changes might be inherited, but most brain and spinal cord tumors in children are not the result of known inherited syndromes. Most gene changes are probably just random events that sometimes happen inside a cell, without having an outside cause.

Other than radiation, there are no known lifestyle-related or environmental factors clearly linked to childhood brain tumors, so it's important to remember that there is nothing these children or their parents could have done to prevent these cancers.