PERP (TP53 apoptosis effector), an EMT-related gene, was significantly downregulated in AIPpos tumors both at the RNA and protein level compared to normal pituitaries (P = 0.01 and 0.03) and to sporadic somatotrophinomas (P = 0.002 and 0.02) (Fig. 2a, b). Here, PERP is linked to growth hormone-producing pituitary gland adenoma.