Doctors often prescribe radiation along with surgery to treat a brain tumor called meningioma that originates in the protective membranes surrounding the brain. But side effects from radiation can be serious, including memory loss and cognitive decline, so it’s important to know which patients really need it. Now, researchers at UC San Francisco and Northwestern Medicine, in collaboration with 10 other medical centers, have found a highly accurate way to predict the best treatment for patients based on patterns of gene expression — which genes are turned on and off — in their tumors.