Ochsner Clinic Foundation 1 article published in JoVE Cancer Research Patient-derived Orthotopic Xenograft Models for Human Urothelial Cell Carcinoma and Colorectal Cancer Tumor Growth and Spontaneous Metastasis Ravan Moret1, Linh Hellmers1, Xin Zhang1, Jessie Gills2, Nathan Hite3, Aaron Klinger3, Grace A. Maresh1, Daniel Canter2,4, Stephen Bardot2,4, David A Margolin3,4, Li Li1,4 1Laboratory of Translational Cancer Research, Institute for Translational Research, Ochsner Clinic Foundation, 2Department of Urology, Ochsner Clinic Foundation, 3Department of Colon and Rectal Surgery, Ochsner Clinic Foundation, 4Ochsner Clinical School, University of Queensland, School of Medicine This protocol describes the generation of patient-derived orthotopic xenograft models by intra-vesically instilling high-grade urothelial cell carcinoma cells or intra-rectally injecting colorectal cancer cells into non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice for primary tumor growth and spontaneous metastases under the influence of lymph node stromal cells, which mimics the progression of human metastatic diseases.