Brain cancer typically involves glial cells (rarely involves neurons). Mature neurons don’t undergo cell division so are not in a position to become cancerous (e.g., cancer is a failure of brakes that stop cellular division thus leading to runaway growth of cells into tumors). Glia do divide and multiply. Cell division is so intricately regulated that it typically requires several failures in the control process to unleash runaway cell division, one reason there will never be the equivalent of a vaccine to cure all cancer. (Fields, R. Douglas, PhD. The Other Brain. p 69-72. NY: Simon & Schuster, 2009.)