POMC and Cushing syndrome: However, in a study of 87 patients [11] in which 74.71 % were diagnosed with Cushing’s disease (CD), 8.05 % with EAS and 17.2 % with ACTH-independent Cushing’s syndrome, the mean serum cortisol suppression with 8 mgs of dexamethasone in the first group was 83.6 %, 52.5 % for the second and 17 % for the third group, showing statistically significant differences only between patients with Cushing’s disease and non-ACTH dependent Cushing’s syndrome, but not between the first group and those with ectopic ACTH secretion.