The uncontrolled proliferation of glia can result in gliomas. One of every two primary brain tumors and one of every five primary spinal cord tumors are composed of glial cells. The most common form of glial tumors, astrocytomas, most often grow in the frontal lobes. (Schramm, Derek D., PhD. The Creative Brain. p 14-16. CA: Institute for Natural Resources, Health Update. 2007.)