Cancer cells compete with the body for food. Some cancer cells use fat to grow, spread, and hide in the brain. When cancer cells hide in the brain, it is hard for chemotherapy reach them due to the blood brain barrier, which allows cancers to come back when they come out of hiding. Dr. Wang and colleagues are investigating how childhood leukemia uses fat to survive in the brain and how drugs that starve leukemia of fat can kill leukemia cells hiding in the brain.