EGFR and ACTH-producing pituitary gland adenoma: In corticotroph adenomas causing Cushing’ disease, somatic mutations in genes encoding deubiquitinases particularly Ubiquitin-Specific Protease 8, and less frequently, ubiquitin-specific protease 48 have been discovered.[21] These mutations enhance epidermal growth factor receptor signaling and increase transcription of pro-opiomelanocortin and secretion of adrenocorticotropic hormone.