Inverse correlation of MYCN and c-MYC mRNA levels in neuroblastoma subtypes. Relative mRNA expression is shown for MYCN and c-MYC as well as for MDM2, DKC1, and PTMA, three direct targets of MYCN/c-MYC. Data are represented as box plots: horizontal boundaries of boxes represent the 25th and 75th percentile. The 50th percentile (median) is denoted by a horizontal line in the box and whiskers above and below extend to the most extreme data point, which is no more than 1.5 times the interquartile range from the box. A set of 251 primary neuroblastoma tumors was analyzed consisting of 138 localized-NA (stage 1/2/3), 30 stage 4s-NA, 52 stage 4-NA and 31 MYCN amplified (AMP) neuroblastoma tumors. Gene expression levels from stage 4s-NA, stage 4-NA, and MYCN amplified tumors were compared pair-wise with those of localized-NA tumors as reference. Differential gene expression was assessed for each gene by using the Mann-Whitney test (cut-off of p < 0.05).