Sen. John McCain's Brain Cancer: What Are Glioblastomas

Sen. John McCain was diagnosed with a type of brain tumor called a glioblastoma, his office confirmed yesterday (July 19).

McCain had surgery on July 14 to remove a blood clot from the area above his left eye. After the procedure, pathologists analyzed the tissue around the clot, and found that the senator had a "primary brain tumor known as a glioblastoma," according to a statement from McCain's office.