DOMINANT AND RECESSIVE MOLECULAR-CHANGES IN NEUROBLASTOMAS

Of all human tumors, neuroblastomas bear the most prominent genetic changes. Amplifications and deletions of chromosomal DNA can be identified by light microscopy on chromosomal spreads of neuroblastoma cells with remarkable frequency and consistency. Consequently, extensive studies have been undertaken to elucidate the molecular basis of these cytogenetic changes. A rich body of information has accumulated on the role played by dominant oncogenes and recessive tumor suppressor genes in the pathogenesis of this disease. Most notably, it was found that amplification of N-myc is responsible for the presence of double minutes and homogeneously staining regions in neuroblastoma chromosomes. It has also been discovered that N-myc amplification is a prognostic sign of malignancy. More recently, recessive genetic alterations in neuroblastoma, such as delation of putative tumor-suppressing genes have received increasing attention, and considerable efforts are being made to identify such genetic elements. Finally, the susceptibility of neuroblastoma cells to differentiating stimuli has made them a popular in vitro system for neurobiological and pharmacological research. The need for suitable in vivo systems has spurred the development of several animal models employing tumor viruses and transgenic technologies.