Shortly after it was revealed that Sen. John McCain was diagnosed with brain cancer, President Obama and Hillary Clinton joined President Trump in sending messages of support to the senator. “John McCain is an American hero & one of the bravest fighters I’ve ever known. Cancer doesn’t know what it’s up against. Give it hell, John,” the former president, who defeated McCain in the 2008 presidential election, wrote on Twitter. “John McCain is as tough as they come. Thinking of John, Cindy, their wonderful children, & their whole family tonight,” Clinton tweeted. In a statement, President Trump said, “Senator John McCain has always been a fighter. Melania and I send our thoughts and prayers to Senator McCain, Cindy, and their entire family. Get well soon.” Doctors discovered a brain tumor known as a glioblastoma after performing emergency surgery on McCain to remove a blood clot. Treatment options include chemotherapy and radiation.