USP8 and familial isolated pituitary adenoma: Regarding cell lineage determinants of PA classification, recent findings have demonstrated that somatotroph adenomas with GNAS wild-type genetic background can express SF1 and that actually driver alterations like USP8 and GNAS in PA can induce changes in tumor transcriptome profiles that could cause clinical characteristics that deviate from WHO 2017 cell lineage classification system (34).