ZEB1 and growth hormone-producing pituitary gland adenoma: Upregulation of ZEB1 (zinc-finger E-box binding homeobox 1), one of the master regulators of EMT, had higher mRNA expression (vs. normal pituitary P = 0.005) and increased nuclear protein expression (vs. normal pituitary P = 0.006; vs. sporadic somatotrophinomas P = 0.01) (Fig. 2a, b).