Frustrated by the slow pace of new drug development for a condition that causes pediatric brain tumors, a neurologist decided to try to fine-tune the animal models used to test new drugs. Instead of studying one mouse model of the disease causing the brain tumors, he evaluated three. They “auditioned” the three models to see which was the best match for neurofibromatosis 1, a genetic condition that increases the risk of brain tumors and afflicts more than 100,000 people in the United States.