John Green said this quote

This is your war now.' I despised myself for the cheesy sentiment, but what else did I have?'Some war,' he said dismissively. 'What am I at war with? My cancer. And what is my cancer? My cancer is me. The tumors are made of me. They're made of me as surely as my brain and my heart are made of me. It is a civil war, Hazel Graze, with a predetermined winner.