University of Utah Health Sciences 1 article published in JoVE Cancer Research Transplantation of Zebrafish Pediatric Brain Tumors into Immune-competent Hosts for Long-term Study of Tumor Cell Behavior and Drug Response Mattie J. Casey*1, Katarzyna Modzelewska*1, Daniela Anderson1, James Goodman1, Elena F. Boer1, Laura Jimenez1, Douglas Grossman1,2, Rodney A. Stewart1 1Department of Oncological Sciences and Huntsman Cancer Institute, University of Utah School of Medicine, 2Department of Dermatology, University of Utah Health Sciences Center, Salt Lake City The transplantation of cancer cells is an important tool for the identification of cancer mechanisms and therapeutic responses. Current techniques depend on immune-incompetent animals. Here, we describe a method to transplant zebrafish tumor cells into immune-competent embryos for the long-term analysis of tumor cell behavior and in vivo drug responses.