In Vivo Tumorigenicity Assays Using Subcutaneous and Orthotopic Xenografts in Immunodeficient Mice

Evaluation of tumorigenic potential of medulloblastoma cell lines in vivo has been the obvious and major next step following cell line driven research for last many years. Effect of changes in expression of gene/s or efficacy of anticancer drugs on tumor initiation and/or growth can be easily assessed by injecting genetically modified cell lines in vivo or by treating in vivo xenografts of established cell lines with newer inhibitors or anticancer drugs. These studies are easy to perform and to reproduce in comparison to patient derived xenografts owing to ease in propagating, maintaining, and modifying genetic makeup of cell lines. Here we describe standardized protocols of obtaining either subcutaneous or orthotopic xenografts of medulloblastoma cell lines in immunodeficient mice. Once established, tumor growth of xenografts can be assessed during the course of experiment by either employing a simple method using Vernier caliper or technically demanding but sensitive method like in vivo bioluminescence imaging. In addition, xenograft tumors of euthanized animals can be preserved as formalin-fixed tissue specimens for further histopathological, immunohistochemical, or molecular analysis.