Moreover, due to the unavailability of human pituitary adenoma cell lines and reproducible animal models, the pace of translational research underlying the pathogenesis and progression was very slow until several studies showed that USP8, USP48, and BRAF are frequently mutated in pituitary corticotroph adenomas, causing CD by enhancing the promoter activity and transcription of the gene encoding POMC, which is the precursor of ACTH (8–10). This evidence concerns the gene USP8 and pituitary gland adenoma.