DNA hypomethylation affects cancer-related biological functions and genes relevant in neuroblastoma pathogenesis

Neuroblastoma pathogenesis has been reported to be closely associated with numerous genetic alterations. However, underlying DNA methylation patterns have not been extensively studied in this developmental malignancy. In this study, we generated microarray-based DNA methylation profiles of primary neuroblastic tumors. Stringent supervised differential methylation analyses allowed us to identify epigenetic changes characteristic for NB tumors as well as for clinical and biological subtypes of NB. We observed that gene-specific loss of DNA methylation is more prevalent than promoter hypermethylation. Overall, the differentially methylated genes showed that functional pathways affected by hypermethylation are different from those affected by hypomethylation. This study provides a comprehensive view of the global DNA methylation profile of NB tumors. Bisulphite converted DNA from the 25 neuroblastic tumor and 2 non patological tissues (fetal brain and adrenal gland) samples were hybridised to the Illumina Infinium 27k Human Methylation