Immunohistochemical demonstration of TGF-beta-receptor type II in human pituitary adenomas.

To investigate whether the signalling pathway of transforming growth factor-beta (TGF-beta) is active in human pituitary tumors, an antibody against TGF-beta-receptor type II (TGF beta-R-II) was prepared to demonstrate immunohistochemically TGF beta-R-II expression in 48 cases of human pituitary adenoma. Positive immunoreactivity for TGF beta-R-II was found in 26 adenomas: 1 of 2 somatotroph cell adenomas, 1 of 9 mammotroph cell adenomas, 0 of 3 mixed somatotroph and mammotroph cell adenomas, 5 of 9 corticotroph cell adenomas, 3 of 3 gonadotroph cell adenomas, 12 of 15 plurihormonal adenomas, and 4 of 7 null cell adenomas. Expression of TGF beta-R-II varied between histological types of adenomas and increased with decreasing grades of differentiation. It is concluded that TGF-beta-mediated signals may be passed via TGF beta-R-II in pituitary tumors.