Some patients with GBM show evidence of infection with a virus called Cytomegalovirus before the time of their diagnosis. CMV is found in the cancer cells of some patients with GBM, suggesting that it may play a role in causing the disease. The cancer cells infected by CMV are able to hide from the body's immune system and escape destruction. We want to see if special white blood cells, called T cells, that have been trained to recognize and kill special parts of CMV infected cells can survive in the blood and affect the tumor.