Patient-derived xenograft (PDX) models can recapitulate patient tumor histopathology, mutational status, gene expression patterns, and drug response with remarkable fidelity. At The Jackson Laboratory, we have established a repository of more than 350 well-characterized PDX tumor models and are working with leading cancer centers on translational studies at the forefront of personalized medicine. This presentation will explore recent progress toward the use of PDX and humanized mouse models for predictive oncology treatment.