Glioblastoma (GBM), also known as glioblastoma multiforme, is the most common and deadly brain tumor in adults. The incidence of GBM in the USA and Europe is 2–3 per 100,000. In Europe, the definition is a bit narrower, with fewer than five in 10,000 (one in every 2,000) people affected. Accordingly, GBM is an orphan disease. Initially, signs and symptoms of glioblastoma are nonspecific. They may include headaches, personality changes, nausea, and symptoms similar to those of a stroke. Symptoms often worsen rapidly and may progress to unconsciousness.