is a malignant (cancerous) brain tumor that develops from a specific type of brain cell called an astrocyte. These cells help support and nourish neurons (nerve cells of the brain) and form scar tissue that helps repair brain damage in response to injury. Glioblastomas are often very aggressive and grow into surrounding brain tissue. Signs and symptoms, such as headache, nausea, vomiting and/or drowsiness, may develop when the tumor begins to put excess pressure on the brain. Affected people may also experience other features depending on the size and location of the tumor. In most cases, the exact underlying cause is unknown; however, they can rarely occur in people with certain genetic syndromes such as neurofibromatosis type 1, Turcot syndrome and Li Fraumeni syndrome. There is currently no cure for glioblastoma. Treatment is palliative and may include surgery, radiation therapy and/or chemotherapy. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.