FIBROBLAST GROWTH-FACTORS AND THEIR RECEPTORS IN PARATHYROID DISEASE

Fibroblast growth factors (FGFs) comprise a family of polypeptide grow th factors implicated in the control of proliferation of glandular tis sues. The aim of this study was to determine whether FGFs are produced in normal and abnormal parathyroid glands and if these tissues have t he potential to respond to this growth factor family. We have examined the expression of FGF receptor (FGF-R) types 1 and 2 and of FGFs 1, 2 , 3, and 7 in a series of human parathyroid tissues using the reverse transcription polymerase chain reaction (RT-PCR). Samples of 10 parath yroid adenomas and 10 hyperplastic glands from patients with renal hyp erparathyroidism (HPT) were compared with samples from normal parathyr oid glands from patients with primary HPT in the study. FGF-R1 was exp ressed in all samples and FGF-R2 in most. FGF1 and FGF2 were expressed in all samples at variable levels, with no correlation between diseas e type and amplified RT-PCR product levels. FGF7 was expressed in norm al parathyroid tissue and in all adenomas but was absent in all but on e of the hyperplastic parathyroid glands from renal failure patients. FGF3 was expressed at low levels in normal tissue and variably express ed in diseased tissue, in some instances at high levels. These finding s suggest that parathyroid tissue is potentially responsive to FGFs. T he absence of FGF7 expression in all but one of the renal parathyroid samples compared with normal and adenomatous tissue requires further i nvestigation. The presence of elevated levels of FGF3 expression in ab normal parathyroid tissue may be significant, as the FGF3 gene (int-2 proto-oncogene) is Located on chromosome 11q13.3, a region already ide ntified as being susceptible to rearrangement/mutation in parathyroid disease.