Genetic and epigenetic alterations in neuroblastoma.

Neuroblastoma is one of the most common solid tumors of childhood. Despite the most recent advances in combined therapy, the overall survival of patients with disseminated disease has not improved in the last 20 years. On the contrary, the increased knowledge of the genetic and molecular abnormalities that characterize neuroblastoma allowed the identification of several important prognostic factors and possible pathways of neuroblastoma development. Moreover, several other structural and numerical non-random chromosome abnormalities were recognized by comparative genomic hybridization and their role is actively investigated. More recently, it has become evident also that epigenetic factors may alter the pattern of expression of multiple genes whose role in neuroblastoma begins to be understood. It is thus likely that a combination of events that include gene translocation and rearrangement and the altered methylation of crucial genes, contribute to neuroblastoma development and progression and are likely responsible for the clinical heterogeneity of this tumor.