Tenosynovial giant cell tumor is a neoplastic disease of joints that can cause severe morbidity. Recurrences are common following local
therapy, and no effective medical
therapy currently exists. Recent work has demonstrated that all cases overexpress
macrophage colony-stimulating factor (CSF1), usually as a consequence of an activating gene translocation, resulting in an influx of macrophages that form the bulk of the
tumor. New anti-CSF1 drugs have been developed; however there are no preclinical models suitable for evaluation of
drug benefits in this disease. In this paper, we describe a novel renal subcapsular xenograft model of
tenosynovial giant cell tumor. Using this model, we demonstrate that an anti-CSF1
monoclonal antibody significantly inhibits host macrophage infiltration into this
tumor. The results from this model support clinical trials of equivalent humanized agents and anti-CSF1R small molecule drugs in cases of
tenosynovial giant cell tumor refractory to conventional local
therapy.