Glioblastoma is the most common high grade (cancerous) primary brain tumour in adults. Glioblastoma belongs to a group of brain tumours known as gliomas as it grows from a type of brain cell called a glial cell.
Glioblastoma is the more common name for a type of brain tumour called a grade 4 astrocytoma. (You may sometimes hear it called glioblastoma multiforme, or GBM for short, though these terms are less used nowadays.)
There are different types of glioblastoma: