Animal models of leptomeningeal metastasis.

Animal models of leptomeningeal metastasis (LM) should give insight into pathophysiological mechanisms and allow to evaluate new treatments including their neurotoxicity. Syngeneic models use tumor cells of mouse, rat, rabbit or guinea pig origin. Allogeneic models usually rely on human tumor cells injected into nude mice or rats. A review of the literature revealed 2 (4) different glioma, 3 medulloblastoma, 3 (3) carcinoma, 3 (1) melanoma, 1 rhabdomyosarcoma, 2 (8) leukemia and 2 (2) non-Hodgkin's lymphoma allogeneic (syngeneic) models of LM. These models have been used to study the evolution of LM and to evaluate systemic or intrathecal chemotherapy, intrathecal immunotherapy (interleukin-2, interferon-beta, uncoupled, toxin- or radionuclide-conjugated antibodies), and recently gene therapeutic approaches. On the whole, pathophysiological, therapeutic and neurotoxic findings have been well transferable to the clinical situation. Therefore, it seems rational to preclinically test new treatments in an appropriate animal model of LM before using them in patients.