Last week, Sen. John McCain underwent surgery to remove a blood clot over his left eye, a procedure that had some questioning whether it might indicate something more serious. Unfortunately, it turned out to be as serious as it gets. Last night, McCain announced that doctors removed a malignant brain tumor called a glioblastoma, a particularly virulent type:

Senator John McCain has announced he is facing one of the most dangerous forms of brain cancer https://t.co/iy0vZAwxkT pic.twitter.com/DJpKocVhcG

— CBS News (@CBSNews) July 20, 2017

CBS News’ chief medical correspondent Dr. Jon LaPook spoke with CBSN on Wednesday night and said that McCain and his family are in for a battle.

“We’re all hoping for the best for him and I would caution against trying to make any prognosis and statistics because everyone is different,” LaPook said.

“A glioblastoma is a primary brain tumor which means it starts in the brain — it didn’t spread there from somewhere else — and it’s a very serious type of brain tumor and even though they have removed it so far as imaging … the fear is that microscopic cells still remain and that’s why they’re [doctors] talking about further treatment.”

Since the diagnosis was announced, support has sounded from all quarters, including two presidents with whom McCain has often sparred. Donald Trump issued a statement that starts off by hailing his tenacity — “Senator John McCain has always been a fighter” — and offers his prayers and support. Barack Obama, who defeated McCain in 2008 and then endured McCain’s potent criticism for the next eight years, told McCain to “Give it hell”:

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.

— Barack Obama (@BarackObama) July 20, 2017

No public message was as touching, however, as that from his daughter Meghan:

Statement regarding my father @SenJohnMcCain: pic.twitter.com/SMte9Hkwkq

— Meghan McCain (@MeghanMcCain) July 20, 2017

McCain’s been giving it hell for his entire adult life. McCain survived years in a brutal POW camp, from which he still bears the scars and disabilities of torture. He’s survived in high-level politics longer than most, refusing to retire after two unsuccessful runs for the presidency to fight for his agenda. Whether you agree or disagree with McCain on policy — and I’ve done plenty of both — his courage, tenacity, and dedication to our country are beyond debate.

Senator McCain and his family will be in my prayers, and I hope yours as well.