osity

MACS

:   magnetic activated cell sorting

Mb

:   megabase

MLPA

:   multiplex ligation‐dependent probe amplification

MNC

:   mono nuclear cell

NGS

:   next generation sequencing

PBS

:   phosphate‐buffered saline

PCR

:   polymerase chain reaction

SCA

:   segmental chromosomal aberration

SNP

:   single nucleotide polymorphism

UHD‐SNP array

:   ultra‐high density SNP array

1. Introduction {#mol2201593545-sec-sec1}
===============

Neuroblastoma, an embryonic tumor arising from the sympathetic nervous system, is the most common extra‐cranial solid tumor in childhood accounting for about 15% of all pediatric cancer deaths ([Maris et al., 2007](#mol2201593545-bib-0008){ref-type="ref"}; [Brodeur, 2003](#mol2201593545-bib-0020){ref-type="ref"}). This disease is characterized by a high degree of clinical heterogeneity, ranging from spontaneous regression ([D\'Angio et al., 1971](#mol2201593545-bib-0015){ref-type="ref"}; [Evans et al., 1976](#mol2201593545-bib-0016){ref-type="ref"}; [Hero et al., 2008](#mol2201593545-bib-0018){ref-type="ref"}) or maturation ([Ambros et al., 1996](#mol2201593545-bib-0002){ref-type="ref"}) to highly malignant courses with widespread metastases and poor outcome. Besides age ([Brodeur et al., 1993](#mol2201593545-bib-0009){ref-type="ref"}; [Cohn et al., 2009](#mol2201593545-bib-0014){ref-type="ref"}), tumor histology ([Shimada et al., 1999](#mol2201593545-bib-0029){ref-type="ref"}), status of *MYCN* oncogene ([Brodeur et al., 1993](#mol2201593545-bib-0009){ref-type="ref"}), and DNA index (ploidy) ([Ladenstein et al., 2001](#mol2201593545-bib-0019){ref-type="ref"}), segmental chromosomal aberrations (SCAs) like 1p and 11q deletions ([Attiyeh et al., 2005](#mol2201593545-bib-0005){ref-type="ref"}; [Caren et al., 2010](#mol2201593545-bib-0011){ref-type="ref"}; [Maris et al., 1995](#mol2201593545-bib-0021){ref-type="ref"}; [Schleiermacher et al., 2011](#mol2201593545-bib-0026){ref-type="ref"}) have been shown to predict tumor behavior and patient out