Pathway Implications of Aberrant Global Methylation in Adrenocortical Cancer

CONTEXT Adrenocortical carcinomas (ACC) are a rare tumor type with a poor five-year survival rate and limited treatment options. OBJECTIVE Understanding of the molecular pathogenesis of this disease has been aided by genomic analyses highlighting alterations in TP53, WNT, and IGF signaling pathways. Further elucidation is needed to reveal therapeutically actionable targets in ACC. DESIGN In this study, global DNA methylation levels were assessed by the Infinium HumanMethylation450 BeadChip Array on 18 ACC tumors and 6 normal adrenal tissues. A new, non-linear correlation approach, the discretization method, assessed the relationship between DNA methylation/gene expression across ACC tumors. RESULTS This correlation analysis revealed epigenetic regulation of genes known to modulate TP53, WNT, and IGF signaling, as well as silencing of the tumor suppressor MARCKS, previously unreported in ACC. CONCLUSIONS DNA methylation may regulate genes known to play a role in ACC pathogenesis as well as known tumor suppressors.