Therefore, the lack or low level of AIP via the lack of ZAC1 upregulation could explain the resistance to treatment with SRLs [4, 30]; (ii) another mechanism for SRLs resistance of AIP mutation positive cases could be the low level of inhibitory G protein which has been identified both in embryonic fibroblast lacking AIP and human pituitary adenomas with AIP mutation [31]. Here, AIP is linked to pituitary gland adenoma.