Harnessing an oncolytic signal and redirecting it against the tumor itself could be developed as a selective strategy for certain cancer types, as occurs with ErbB hyperactivity, a form of signaling that drives many carcinomas. Inspired by this idea, scientists at Stanford University have engineered a virus that replicates only in ErbB-hyperactive ovarian cancer cells. This allowed them to precisely kill this specific tumor population, achieving greater efficacy and safety than previous oncolytic viruses.