If you are found to be eligible to take part in this study, you will take 2-4 nilotinib capsules or tablets by mouth 2 times a day (4-8 capsules or tablets a day total) every day, at least 8 hours apart. Nilotinib should be taken each morning and evening with a large glass of water. The study medication will be given to you every 3 - 12 months. You will also be given a "pill diary" to write down when (day and time) you take the drug. You will also write in the diary any side effects you may experience. You should bring the diary, any unused capsules or tablets, and empty containers of nilotinib with you to every visit to the study doctor. Any unused supplies must be returned at the end of the study.