A type of brain cancers called “diffuse gliomas” currently lacks effective treatments. One obstacle to developing new therapies is the disease variability between patients. Several categories of diffuse gliomas have been identified. However, we know that even within each of these categories, the tumors can vary substantially. This includes differences in the specific genetic lesions that are present in the tumors. Those are particularly obvious as the diseases progress. Indeed, during progression, diffuse gliomas frequently accumulate new genetic lesions. We know very little about the impact of these accumulating lesions. They could make the disease more aggressive, and either more or less responsive to specific treatments. Our goal is to understand how genetic lesions that occur during disease progression shape the growth of the gliomas, and their response to a drug that recently entered the clinic. We will achieve this by developing and studying a new animal model of diffuse glioma evolution. We expect that our studies will help the design of better treatments that are tailored to individual patients.