The cause of glioma is unknown, but genetics may play a role in determining risk.

Genes control the functions inside a cell. Special genes control how cells divide and grow. Cancer occurs when the damaged genes stimulate the cell to multiply out of control. The exact cause for this damage is unknown.

Examples:

• DNA
• Genes on chromosomes
• Cancer cells
• Cancer cell division

Brain tumors cause damage by causing swelling, by placing pressure against parts of the brain, or by increasing pressure inside the skull.