The Associated Press is reporting that Sen. Edward Kennedy (D-Mass.) has been diagnosed with a malignant brain tumor. The tumor, on Kennedy's left parietal lobe, is known as a "malignant glioma," and was discovered when doctors conducted tests after Kennedy suffered a seizure over the weekend. The tumor has been determined to have been the cause of the seizure. The 76-year-old senator has been hospitalized in Boston since Saturday, and doctors have not yet given......