The best thing you can do for your friend right now is to be really open, honest and frank with her in talking about this issue. She is going to find that everyone around her will do everything they can to avoid talking to her - not out of meanness, but because they simply don't know what to say and feel really bad about this fact. People also sometimes feel guilty because they're fine and the other person's not. I would sit down with her during recess or lunch or whatever and just talk to her ... don't be afraid to ask her questions about her illness, how she found out, what her treatment options are, etc. She is probably really wanting to share all her thoughts and fears about this with someone her own age who won't react badly to it - you need to be that person, if you can. Offer her a listening ear, a shoulder to cry on if she needs it and a helping hand in any way you can (like making sure if she misses something at school, that you'll help her to pick it up later, etc.). Try to be as positive as you can about her prospects, and try to help her to not get really down (which she inevitably will at varying stages of her treatment, which can be really harsh). Remember too, many people survive cancer, and she could well be one of them. I will pray for you both - her for surviving her illness and you for maintaining the strength of character to continue supporting her throughout her ordeal. For even thinking about this, you must already be a really good friend.