Glioblastoma multiforme, the brain cancer that killed Sen. Edward Kennedy, is aggressive and incurable. Researchers can now demonstrate delivery of a drug that turns off a critical gene in this complex cancer, increasing survival rates significantly in animals with the disease. The therapeutic, based on nanotechnology, is nimble enough to cross the blood-brain barrier and get to the brain tumor. Once there, it flips the switch of the oncogene to "off," silencing the gene.