As of 2015, there is no empirical evidence that indicates specific causes of glioblastoma, states the American Brain Tumor Association. However, there are some risk factors commonly associated with brain glioblastomas, such as radiation to the head during childhood, rare genetic conditions and age, explains WebMD.
Research shows that people who receive radiation to the head in childhood have an increased risk of developing a brain tumor in adulthood, according to WebMD. Other at-risk groups include individuals with Li-Fraumeni syndrome and those over 65.
Glioblastomas often occur in the cerebral hemispheres, but they can also grow in other parts of the brain and in the spinal cord, notes the American Brain Tumor Association. Glioblastomas typically arise from astrocytes, the rapidly dividing cells that make up the brain's supportive tissue.
The tendency of glioblastomas to arise from the quickly dividing astrocytes increases the likelihood of cancer, though not all glioblastomas are malignant, says WebMD. There are two main types, primary, or de novo, and secondary. Primary glioblastomas tend to grow very quickly. Secondary glioblastomas grow slowly by comparison, according to the American Brain Tumor Association.
Glioblastomas are often a combination of many different types of cells and matter, such as blood vessels, calcium deposits and cystic mineral, explains the American Brain Tumor Association. Nourished by a generous blood supply, glioblastomas grow quickly, and dead cells typically comprise the center of the tumor.