WASHINGTON - Arizona Sen. John McCain says he's grateful for the outpouring of support after his brain cancer diagnosis. He's promising to be back soon.

  

In a tweet Thursday, McCain says: "I greatly appreciate the outpouring of support - unfortunately for my sparring partners in Congress, I'll be back soon, so stand-by! "

 

McCain's office said late Wednesday that the 80-year-old senator had been diagnosed with cancer. Doctors in Arizona removed a blood clot above his left eye last Friday. Pathology tests revealed a brain tumor associated with the clot.

  

McCain has been recuperating at his home in Arizona.