The exact cause of brain cancer is not known, states WebMD. Several things have been associated with brain cancer, including HIV infection, genetic factors, environmental toxins, smoking and radiation. In most cases, doctors cannot identify a precise cause of a brain cancer.
Brain tumors are an irregular growth of cells in the brain disrupting its normal function. Such growths are usually known as brain tumors, but not all tumors are cancerous. Brain cancer is typically used to refer to malignant brain tumors, notes WebMD.
Naming of the tumors depend on where they originated and whether they are cancerous. Benign tumors start from the brain and they develop slowly. They do not have cancer cells and do not spread to other tissues. Malignant tumors have cancer cells, grow rapidly and attack surrounding tissues.
Primary tumors start from the cells of the brain and may spread to the brain and spine, but not to other body organs. Secondary or metastatic tumors originate from other organs or parts of the body and spread to the brain. These tumors are more common than primary tumors and are named depending on where they originated. There are over 120 types of brain and nervous system tumors, according to the National Brain Tumor Society.