PHOENIX — Republican Senator John McCain has been diagnosed with brain cancer. <br /> <br />According to a news release from the Mayo Clinic Hospital in Phoenix, where McCain had his operation, surgeons found a malignant tumor following a procedure to remove a blood clot from above his left eye. <br /> <br />Pathology following the procedure showed the tissue to be an aggressive grade four glioblastoma, notes the release. The tumor and tissue of concern were completely removed. <br /> <br />McCain is said to be doing “amazingly well” following the procedure and is recovering at home. <br /> <br />His follow-up treatment options include a radiation and chemotherapy.