POMC and Cushing syndrome due to macronodular adrenal hyperplasia: By examining these gene expression profiles, we sought to identify the common and unique molecular features of these tumors to elucidate the underlying biology of ectopic ACTH-secreting tumors, discover potential diagnostic biomarkers, and explore new therapeutic avenues that could improve the management of patients with Cushing’s syndrome due to ACTH hypersecretion.