Using Zebrafish Larvae as a Xenotransplantation Model to Study Ewing Sarcoma

Tumor models allowing for the in vivo investigation of molecular mechanisms driving tumor progression and metastasis are important to develop novel strategies for cancer treatment. Unfortunately, for Ewing sarcoma, no adequate genetic animal models are currently available, although there is progress in zebrafish. Nevertheless, mouse xenotransplantation models are the state-of-the-art to model Ewing sarcoma in vivo. Here, we describe an alternative Ewing sarcoma xenotransplantation model in embryonic and larval zebrafish. This zebrafish model offers live imaging and easy compound testing opportunities, thereby complementing mouse xenotransplantation models. In this chapter, we provide a detailed protocol for how to xenograft Ewing sarcoma cells into 2-day-old zebrafish and how xenografted zebrafish can be imaged and analyzed over consecutive days to study tumor proliferation and response to small compound treatment.