To test whether promoter hypermethylation and consequent RASSF1A silencing contributes to adrenocortical tumorigenesis, we first determined the methylation status of CpG island A of RASSF1 in fresh-frozen ACC (n = 7), ACA (adrenocortical adenoma; n = 8) and normal adrenal cortex (n = 6) tissue specimens. The gene discussed is RASSF1; the disease is adrenal cortex carcinoma.