Differential methylation analysis. (A) Analysis of differences in methylation beta values from patients with no evidence of disease (NED) compared to those with an adverse outcome (DOD) for the most statistically significant genes. One of the CpG sites from the Illumina methylation array is shown. Box plot explanation; upper and lower hinges of the box represent the 75th percentile and 25th percentile respectively; whiskers indicate the highest and lowest values that are not outliers or extreme values; thick horizontal line within box, median. Open circles represent outliers and asterisks represent extremes. The p-value at gene-by-gene level is indicated in the left lower corner in each graph. (B) Analysis of methylation frequencies for tumors with different chromosomal profiles. For definition of chromosomal groups, see Carén et al . CpG sites for SCNN1A and DUSP23 are shown. The highest methylation frequencies in SCNN1A are found in NB tumors with an unfavorable chromosomal profile. Methylation of DUSP23 is almost mutually exclusive in MYCN-amplified NBs.