Glioblastomas are the most common and aggressive primary brain tumours, have been called grow and go tumours. They donít grow rapidly at a given site, they also move rapidly to new sites. The exact causes of Glioblastoma are still unknown. In general, tumors are abnormal growths, or mutations, of brain cells. However, it remains a mystery how these abnormalities occur. The symptoms of Glioblastoma are highly dependent on the location of the tumor in the brain. In many cases, the symptoms are not visible until the tumor becomes large.