Molecular Therapy for Neuroblastoma

Abstract

Despite the generally held notion that embryonal cancers are simpler from a genetic standpoint than adult neoplasms, these cancers show multiple chromosomal rearrangements, suggesting a complicated series of acquired alterations during malignant evolution. This is best exemplified in neuroblastoma, an enigmatic and highly heterogeneous pediatric neoplasm that accounts for 15% of pediatric cancer mortality and remains an important clinical problem in which tumor genomics correlate with disease phenotype (George et al. 2007). Neuroblastoma represents a spectrum of diseases, and distinct patient subsets exist based on tumor biological features (Maris 2005). Low-risk neuroblastomas are likely characterized by mitotic dysfunction leading to a hyperdiploid modal karyotype with whole chromosome gains, but few, if any, structural cytogenetic rearrangements. These tumors may regress spontaneously, differentiate, or respond completely to modest doses of chemotherapy. In contrast, aggressive neuroblastomas are characterized by complex segmental chromosomal aberrations. Two main categories of unfavorable neuroblastomas exist, with a well-defined subset (approximately 40%) defined by deletion of the short arm of chromosome 1 and MYCN amplification. On the other hand, the majority of aggressive neuroblastomas show multiple other chromosomal rearrangements, most frequently involving chromosome 11q (Attiyeh et al. 2005).