Neurotrophin signal transduction in medulloblastoma.

The members of the neurotrophin family play key biological roles in the development of the nervous system. Based on studies initially in cell lines (e.g., the rat pheochromocytoma PC12 cells), neurotrophins have been found to be important mediators of proliferation, differentiation, and survival in the normal brain, but their role in brain tumors remains unclear. Since neurotrophins and neurotrophin receptors are frequently detected in biopsy samples of central nervous system medulloblastomas, efforts have been undertaken in several laboratories to elucidate the potential effects of neurotrophins on the growth and differentiation of these tumors. Results from these studies may have both basic and clinical implications because medulloblastomas resemble embryonic neuroectodermal stem cells and/or their immature neuronal and glial progeny. This review focuses on recent developments in our understanding of the role of neurotrophins in medulloblastomas, especially the ability of nerve growth factor to induce apoptosis in vitro in medulloblastomas.