<qa>  What is the gene mutation that causes the receptor for a protein called epidermal growth factorThis study will examine tissue from gliomas a type of brain tumor removed during surgery for gene mutations, or changes, thought to be involved in tumor formation and growth. One common gene mutation causes the receptor for a protein called epidermal growth factor EGF to be in an active state all of the time, allowing uncontrolled cell growth that can lead to tumor formation. This study will analyze blood and tumor tissue samples from patients with gliomas for: 