Spontaneous pattern formation provides a physical basis for morphogenesis, as put forth by D’Arcy Thompson and Turing. In this talk, I will discuss ongoing work to understand collective invasion during metastasis using similar principles. We study as a model system patient-derived breast cancer organoids in collagen matrices developed by the Khalil group at Utrecht. We propose a hypothesis for a positive feedback loop driving collective invasion, which involves an interplay between mechanical and chemical activity of cells and the nonlinear mechanics of collagen. We examine the consequences of this hypotheses using mathematical and computational modeling. I will also present preliminary experiments testing the proposed mechanism.