Recent advances in genetic analysis of this heterogeneous tumour, using a wide panel of techniques including array Comparative Genomic Hybridization, have revealed different recurrent genomic aberrations, most of which consist of copy number alterations. Indeed, it is now well established that the overall genomic pattern is an important prognostic marker which might be taken into account for treatment stratification. Numerical chromosome alterations are observed in NBs with good prognosis when exclusive. Typical segmental copy number alterations are associated with poor outcome. Amplification of the proto-oncogene MYCN, found in 25 to 30% of NBs, is the most important genomic feature, in terms of prognosis and impact on treatment decisions. Other genomic aberrations defined by regional amplifications targeting various sites, non syntenic with the MYCN locus, have been previously described. These amplicons seem to have a low recurrence and most often occur concomitantly with MNA. In a previous study, the precise genetic mapping of such amplicons has been described, and a poor survival for patients with NBs harbouring loci co-amplified or not with MYCN has been suggested. Nevertheless, to date, clinical features of NB harbouring amplicons different from MYCN, and particularly without concurrent MNA, have not yet been reported in detail. The role of these amplicons and their possible contribution to the oncogenic process are LY2109761 unclear and there is a need to better characterise clinically these tumours. The aim of this study is to describe occurrence, detailed clinical characteristics, histology and outcome of NBs harbouring amplicons at loci distinct from MYCN, without and with MNA. Given the resolution of the arrays used in this study, it cannot be excluded that amplified SCH772984 regions smaller than the interval between the probes of the arrays might have gone undetected by our techniques. However only few amplified regions distinct from MYCN have been observed in recent high resolution sequencing studies based on whole exome/genome sequencing, confirming that this is a rare phenomenon. Thus our lower resolution approaches give a good overview of the majority of amplicons in the genome.