CDKN1B and ACTH-producing pituitary gland adenoma: Until recently, there were only few reports regarding the genetic changes in ACTHomas, except for familial Cushing’s disease, such as multiple endocrine neoplasm type 1 (MEN1), MEN4, and familial isolated pituitary adenomas (FIPAs), and the germline mutations associated with these hereditary syndromes were identified in the MEN1, CDKN1B, and AIP genes, respectively.