BASIC FIBROBLAST GROWTH-FACTOR EXPRESSION BY 2 PROLACTIN AND THYROTROPIN-PRODUCING PITUITARY-ADENOMAS

We investigated the expression of basic fibroblast growth factor (bFGF ) in an aggressive type of PRL and TSH-producing pituitary adenoma. Im munocytochemistry and electron microscopy were used to characterize th e tumors removed from two patients. Immunoassays were used to measure hormone and bFGF levels in vitro and in vivo. Reverse transcription-po lymerase chain reaction (RT-PCR) was used to detect bFGF mRNA expressi on by these tumors. Morphologically, these tumors were characterized b y an unusual plurihormonal pattern with expression of PRL and TSH and the ultrastructural characteristics of the silent subtype 3 adenoma; i n addition, both adenomas displayed marked interstitial fibrosis. bFGF was measurable in the circulation of these patients ranging from 7.5- 20.5 pg/mL (normal < 1 pg/mL). bFGF concentrations were reduced follow ing surgical adenomectomy. bFGF in culture media was present in concen trations of 197-387 pg/24h/10(5) cells, bFGF mRNA expression was ident ified in both adenomas examined. bFGF levels were unaltered in the cul ture media and in the serum of patients following GnRH and TRH treatme nt. In conclusion, the expression of bFGF by these plurihormonal pitui tary adenomas suggests the possibility that it may play a role in the development of fibrosis and tumor cell proliferation of this unusual t ype of pituitary neoplasm.