Increased WSB1 copy number correlates with its over-expression which associates with increased survival in neuroblastoma

Gain of chromosome 17 is the most prevalent genetic abnormality identified in neuroblastoma (NB) and distal 17q gain has prognostic significance in NIB. In this report, we have combined array-based comparative genomic hybridization (A-CGH) and gene expression analysis to investigate gene copy number changes and its impact on the gene expression level as well as their association with prognosis genes located on chromosome 17 in NB tumors. We observed differential gains of chromosome 17 between Stages 4- and 4S tumors. We found that WSB1, mapping to 17q11.1, which was frequently gained in 4S- tumors and not changed in 4- tumors, showed strong correlations between expression level and copy number. Furthermore, the increase of WSB1 gene expression is associated with good outcome in patients with NB of all stages. WSB1 also enhances the prognostic prediction when combined with other current prognostic factors in NB. Our results demonstrate that WSB1 copy number correlates with its expression level and that its high expression associates with good prognosis suggesting a possible role of this gene in the biology of favorable outcome NB. This article contains Supplementary Material available at http://www. interscience.wiIey.com/jpages/1045-2257/suppmat. Published 2006 Wiley-Liss, Inc.