Animal models of medulloblastomas and related primitive neuroectodermal tumors. A review

Primitive neuroectodermal tumors (PNET) belong to a family of pediatric neoplasms of the central nervous system (CNS) that are composed predominantly of primitive neuroepithelial cells. Among the different CNS PNET, those arising in the posterior fossa (i.e. medulloblastomas) are prototypical of this group of brain tumors. The basic cell biology of PNET is incompletely understood, but recent studies of human PNET biopsies and cell lines derived therefrom demonstrate that neoplastic cells in human PNET recapitulate many of the phenotypic properties of immature CNS neurons or their progenitors. Based on these findings, it has been possible to develop several animal models of human PNET that will enhance efforts to gain fundamental insights into the induction and progression of PNET. In addition, these model systems will enable emerging gene therapies to be targeted specifically for human PNET. Accordingly, this review summarizes current understanding of the cell biology of human PNET, particularly medulloblastomas, and it highlights the most salient features of representative in vivo model systems of human PNET that are relevant to future studies of these tumors.