Causes of brain tumors
Brain tumors that start as a growth of cells in the brain are called primary brain tumors. They might start right in the brain or in the tissue nearby. Nearby tissue might include the membranes that cover the brain, called meninges. Brain tumors also can happen in nerves, the pituitary gland and the pineal gland. Brain tumors happen when cells in or near the brain get changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. The changes tell the cells to grow quickly and continue living when healthy cells would die as part of their natural life cycle. This makes a lot of extra cells in the brain. The cells can form a growth called a tumor. It's not clear what causes the DNA changes that lead to brain tumors. For many people with brain tumors, the cause is never known. Sometimes parents pass DNA changes to their children. The changes can increase the risk of having a brain tumor. These hereditary brain tumors are rare. If you have a family history of brain tumors, talk about it with your health care provider. You might consider meeting with a health care provider trained in genetics to understand whether your family history increases your risk of having a brain tumor. When brain tumors happen in children, they're likely to be primary brain tumors. In adults, brain tumors are more likely to be cancer that started somewhere else and spread to the brain. Cancer that spreads to the brain Brain metastases Brain metastasesOpen pop-up dialog box Secondary brain tumors happen when cancer starts somewhere else and spreads to the brain. When cancer spreads, it's called metastatic cancer. Any cancer can spread to the brain, but common types include: Breast cancer. Colon cancer. Kidney cancer. Lung cancer. Melanoma. It's not clear why some cancers spread to the brain and others are more likely to spread to other places. Secondary brain tumors most often happen in people who have a history of cancer. Rarely, a brain tumor may be the first sign of cancer that began somewhere else in the body. In adults, secondary brain tumors are far more common than are primary brain tumors.