Paediatric brain tumours: an embryological perspective

Primitive neuroectodermal rumours are amongst the most common paediatric tu mours of the central nervous system. These tumours are composed of undiffer entiated cells and a variable component of more differentiated cell types. Most analysis of these tumours has focused on molecules normally found in t he differentiated cells or those found in all primitive neuronal precursors . In this article we describe recent advances in understanding of the molec ular processes involved in normal neurogenesis. We discuss the relevance of these data to the biology of neuronal tumours and describe strategies we a nd others have adopted to investigate the usefulness of molecules found in undifferentiated neuronal tissues in understanding the events which underli e oncogenesis in this tumour type.