A novel murine model of human renal cell carcinoma spinal metastasis

There is currently no reproducible animal model of renal cell carcinoma (RCC) spinal metastasis that allows for laboratory study of the human disease. In this report, we describe an animal model that reliably reproduces RCC spinal metastasis using a human tumor cell line. A posterior surgical approach was used to implant tumor cells into the lamina of immunosuppressed mice. Histology sections were analyzed 12 weeks after tumor cell implantation to quantify the location and extent of tumor growth. RCC xenografts grew in treated animals (8 mice) with a reproducible pattern of growth. After implantation, tumor growth occurred primarily in the antero-posterior dimension. At 8 weeks after tumor cell implantation, there was visible tumor growth in all treated mice. Histologic correlation at 12 weeks after tumor cell implantation confirmed tumor growth involving primarily the paraspinal region and lamina. Our investigation resulted in an orthotopic model of human RCC spinal metastasis. Ultimately this will allow testing of targeted therapies for RCC with spinal involvement. Furthermore, this model can be expanded to develop similar spinal metastasis models for other tumor cell lines.