EGFR and ACTH-producing pituitary gland adenoma: Gefitinib, a TKI-targeting EGFR, suppresses expression of POMC and ACTH secretion in murine and canine corticotroph adenoma cell cultures, suppresses expression of POMC in human corticotroph adenoma cell cultures, as well as attenuating the growth and ACTH secretion of EGFR-expressing tumors in vivo in mice [55].