Light micrograph of a section of the brain with a glioblastoma. Glioblastomas are a fast growing type of brain tumour. It is the most aggressive and most common type of cancer that originates in the brain. Initial symptoms include headaches, personality changes, seizures and memory loss. The presence of microvascular proliferation and necrosis (cell death) is one of the histologic hallmarks of glioblastoma. Necrotic areas typically appear in a serpentine or geographic pattern within highly cellular areas. Anti-GFAP (Glial Fibrillary Acidic Protein) antibody stain. Magnification: 556x when printed at 10 centimetres.