Unraveling the Causes of Brain Tumors
There are many types of brain tumors. Unfortunately, the cause behind most of these tumors remains a mystery.
There are more than 120 different types of spinal cord and brain tumors. These tumors, also called central nervous system (CNS) tumors, are sometimes benign (non-cancerous) and sometimes cancerous.
In addition, some tumor types occur more often in children than in adults. And adult tumors are not the same as children’s tumors.
Brain Tumor: Risk Factors
Certain factors have been found to increase a person’s risk for a spinal cord or brain tumor. These include:
- Being a Caucasian male
- Being older than 70
- Being younger than age 8
- Having a family history of brain tumors
- Being exposed to radiation
- Being exposed to certain chemicals
But just because a person may be at risk for a brain tumor, doesn’t mean they will get one. What these factors tell us is that people who get a brain tumor often fall into the above categories.
Brain Tumor: Genetic Disorders
While researchers do not know much about what causes brain and spinal cord tumors, they do know that some genetic disorders cause brain tumors. But fewer than 5 percent of brain tumors result from these genetic disorders, including neurofibromatosis, a condition in which nerve tissues grow tumors.
That leaves 95 percent of all brain tumors whose cause is not yet known. But research is under way to better understand what causes brain and spinal cord tumors.
Brain Tumor: The Cancer Genome Atlas
“The most exciting new initiative is the Cancer Genome Atlas,” says Andrew Sloan, MD, director of the Brain Tumor and Neuro-Oncology Center at University Hospitals Case Medical Center in Cleveland. The Cancer Genome Atlas Research Network is a collaborative effort funded by the National Cancer Institute (NCI) and the National Human Genome Research Institute of the National Institutes of Health.
The network, whose goal is to discover more about the molecular basis of cancer, recently published the first results of a major, comprehensive study of glioblastoma. Glioblastomas account for 23 percent of brain tumors diagnosed in the United States.
In the study, researchers examined brain tumor samples from 206 patients. They found numerous gene mutations (changes) that occur in glioblastomas (more than 300 are already known). But they also found three genetic mutations that occur frequently but had not been recognized before. The team was also able to identify some of the main biological pathways that are disrupted in glioblastomas.
Johns Hopkins researchers published similar findings from a parallel but smaller study on the same day. “These are very exciting studies because they give us hope: Rather than having to fight the 300 or 400 known genetic defects in glioblastomas, we may be able to focus on far fewer to help us find the cause of these tumors,” Sloan says. “This would make the puzzle much easier to solve.”
Because most glioblastoma patients die within 14 months of being diagnosed, finding a cause of this deadly form of cancer could help doctors design treatments that would enable people to live longer.
Brain Tumor: International Study
Another large project, the Gliogene study, is the largest study to date of a primary brain tumor called a glioma. In the five-year study, an international team of researchers will try to identify what gene or genes are related to their development. A glioma is a common type of brain tumor that grows from nerve cells, called glial cells, which are important to brain tissue support.
If they can find those genes, they may be able to identify a genetic link among the relatives of people with brain tumors and use it to develop new treatment and perhaps improve existing ones. The hope is that one day the findings might even help researchers develop ways to prevent this kind of brain tumor.
The researchers’ goal is to screen more than 15,000 people around the world. Countries that are participating are the United States, United Kingdom, Sweden, Denmark and Israel. If you, or a member of your family, have a brain tumor and you are interested in participating in this study, visit Gliogene: An International Brain Tumor Family Study .
Brain Tumor: Rembrandt Is More Than a Painter
To do accurate research, scientists need a base of genetic information about brain tumors that is properly gathered and stored. Together, the NCI and National Institute of Neurological Disorders and Stroke (NINDS) have created such a database, the Repository for Molecular Brain Neoplasia Data (REMBRANDT). The repository will keep analyses of samples from brain tumors and other data on all types of brain tumors to provide researchers with invaluable information for their studies.