The first group, derived from NR5A1, includes clinically non‐functioning PA (CNFPA), gonadotrophinomas, and null cell; the second includes adrenocorticotropic hormone (ACTH) adenomas and silent corticotroph adenomas (SCAs) and is driven by TBX19; the third are the POU1F1‐originating thyroid-stimulating hormone (TSH), prolactin (PRL), and growth hormone (GH) adenomas. This evidence concerns the gene POU1F1 and adenoma.