we wish to report some corrections to our study , none of which alters the interpretation of the data or the conclusions drawn . after publication
, we noticed that one of the micro - array hybridizations ( on sample nb11 ) was performed on the same patient 's material as another hybridization ( sample nb4 ; see table 1 ; a corrected version of table 5 ) .
as this error leads to an incorrect subclassification of the patients into the ' favourable ' and ' unfavourable ' neuroblastoma subgroups , we would like to exclude this data point from the differential expression analysis of favorable versus unfavorable neuroblastoma given under the heading ' differential expression analysis of favorable and unfavorable neuroblastoma ' in the results section of .
careful reanalysis after exclusion of nb11 did not lead to important changes in the generated gene lists and conclusions ; the changes are given in the corrected paragraph and table 2 ( a corrected version of table 4 ) , and the additional data files 1 and 2 ( corrected versions of additional data files 2 and 3 ) available online with this article . we also noticed that sample nb1 is stage 1 instead of stage 4s and that sample nb2 was not localized to the adrenals ( see table 1 ) .
so far , most published microarray studies on neuroblastomas mainly compared favorable with unfavorable neuroblastomas in order to identify prognostic markers or pathways that are involved in these clearly different neuroblastoma tumor types . in order to add value to such an analysis
, we contrasted similar differentially expressed gene lists with the normal neuroblast expression profile ( additional data file 1 ) . in a first step , we compared the differentially expressed genes between these two tumor types with published prognostic gene lists .
we found that 23 of the 193 genes on our list were previously reported , including the well established markers mycn , ntrk1 , and cd44 ( see nbgs analysis in additional data file 2 ) .
subsequently , we looked for the corresponding gene expression levels of the differentially expressed genes in the normal counterpart cells , aiming to select neuroblastoma candidate genes .
of the 100 genes that are more highly expressed in favorable tumors ( compared to unfavorable ) 41 also have a significant differential expression ( either higher or lower ) compared to neuroblasts , whereas 43 of the 93 genes that are more highly expressed in unfavorable tumors exhibit differential expression compared to the neuroblasts ( table 2 ) . from this analysis ,
a few putative positional tumor suppressor candidates emerge : cdc42 on 1p36 , cacna2d3 on 3p21 and dlk1 on 14q .
the latter two genes are of particular interest because they are highly expressed in neuroblasts and favorable neuroblastomas and their expression is significantly lower in unfavorable neuroblastomas . among the genes that are
more highly expressed in unfavorable neurob - lastomas than in favorable ones and neuroblasts , the proven oncogenic transcription factor mycn emerges ( and putative downstream genes kifap3 , ophn1 , rgs7 , ascl1 , odc1 , twist1 and tyms , according to nbgs ) , as well as several other genes that have been identified or studied in the context of neuroblastoma such as alk and prame , and positional candidates on 17q including birc5 and rnu2 .
so far , most published microarray studies on neuroblastomas mainly compared favorable with unfavorable neuroblastomas in order to identify prognostic markers or pathways that are involved in these clearly different neuroblastoma tumor types . in order to add value to such an analysis
, we contrasted similar differentially expressed gene lists with the normal neuroblast expression profile ( additional data file 1 ) . in a first step , we compared the differentially expressed genes between these two tumor types with published prognostic gene lists .
we found that 23 of the 193 genes on our list were previously reported , including the well established markers mycn , ntrk1 , and cd44 ( see nbgs analysis in additional data file 2 ) .
subsequently , we looked for the corresponding gene expression levels of the differentially expressed genes in the normal counterpart cells , aiming to select neuroblastoma candidate genes .
of the 100 genes that are more highly expressed in favorable tumors ( compared to unfavorable ) 41 also have a significant differential expression ( either higher or lower ) compared to neuroblasts , whereas 43 of the 93 genes that are more highly expressed in unfavorable tumors exhibit differential expression compared to the neuroblasts ( table 2 ) . from this analysis ,
a few putative positional tumor suppressor candidates emerge : cdc42 on 1p36 , cacna2d3 on 3p21 and dlk1 on 14q .
the latter two genes are of particular interest because they are highly expressed in neuroblasts and favorable neuroblastomas and their expression is significantly lower in unfavorable neuroblastomas . among the genes that are
more highly expressed in unfavorable neurob - lastomas than in favorable ones and neuroblasts , the proven oncogenic transcription factor mycn emerges ( and putative downstream genes kifap3 , ophn1 , rgs7 , ascl1 , odc1 , twist1 and tyms , according to nbgs ) , as well as several other genes that have been identified or studied in the context of neuroblastoma such as alk and prame , and positional candidates on 17q including birc5 and rnu2 .
additional data files 1 and 2 containing the corrected data available online with this article .
corrected version of additional data file 2 . corrected version of additional data file 3 .
clinical and genetic data of carefully selected neuroblastoma samples that were included in this study samples were subdivided into favorable or unfavorable type based on mycn amplification , ploidy and age at diagnosis .
nd , not determined or unknown . genes that are differentially expressed in favorable vs unfavorable neuroblastoma genes that are differentially expressed compared with neuroblasts among the differentially expressed genes in favorable neuroblastoma ( nb ) vs unfavorable nb , with an indication of the number of neuroblastoma microarray studies in which these genes were found through nbgs analysis .
 a correction to human fetal neuroblast and neuroblastoma transcriptome analysis confirms neuroblast origin and highlights neuroblastoma candidate genes by k de preter , j vandesompele , p heimann , n yigit , s beckman , a schramm , a eggert , rl stallings , y benoit , m renard , a de paepe , g laureys , s phlman and f speleman . 
 genome biology 2006 7:r84 