Brain cancers are either primary (starting in the brain) or metastatic (starting somewhere else in the body and then moving to the brain). Gliomas are primary brain tumors involving glial cells, which provide nutrients, oxygen, and other support to neurons (nerve cells). Malignant (characterized by progressive and uncontrolled growth) gliomas are the most common primary brain tumors, accounting for about 10 000 primary malignant brain tumors diagnosed yearly in the United States. They are a common cause of cancer death in persons 15 to 44 years old and affect more men than women. Senator Edward Kennedy recently died of a malignant glioma. The March 10, 2010, issue of JAMA includes an article about a woman with a glioma.