Integrated genome-wide methylation and gene expression profiling of aldosteronomas (n = 25), normal adrenal cortical tissue (n = 10) and nonfunctioning adrenocortical tumors (n = 13) has determined that altered methylation in aldosteronomas is associated with dysregulated expression of genes involved in steroid biosynthesis. Specifically, AVPR1A and PRKCA were downregulated and hypermethylated, and CYP11B2 was upregulated and hypomethylated in aldosteronomas.