The overall focus of the Ornitz laboratory is on the in vivo functions of Fibroblast Growth Factors (FGFs), their interactions with other signaling pathways, and their role in development, tissue homeostasis, regeneration, and injury response. We use in vivo mouse models to study mechanisms of organogenesis and we apply our knowledge of developmental mechanisms to understand how growth factors regulate tissue homeostasis, and how reactivation of developmental programs function in tissue regeneration and injury response.