Some somatic mutations, like GNAS gain-of-function mutation identified in 30% of somatotropinomas, GPR101 mutation identified in 4% of somatotropinomas and USP8 mutation identified in 40% of corticotrophinomas, are not clearly associated with tumor behavior (Reincke et al. 2015, Chen et al. 2018, Sbiera et al. 2019). This evidence concerns the gene GNAS and growth hormone-producing pituitary gland neoplasm.