Immunohistochemical Expression of Insulin-Like Growth Factor-1, Transforming Growth Factor-Beta1, and Vascular Endothelial Growth Factor In Parathyroid Adenoma and Hyperplasia

Abstract

Background: Insulin-like growth factor (IGF), transforming growth factor-beta1 (TGF-beta 1), and vascular endothelial growth factor (VEGF) are commonly studied growth factors, but little data are available on the immunohistochemical expression of these factors in parathyroid lesions. Materials and Methods: Tissue specimens from 36 patients with primary hyperparathyroidism (P-HPT) (26 adenomas and 10 primary hyperplasias) were examined. Normal parathyroid tissue adjacent to the adenoma or area of hyperplasia was used as control tissue. Preoperative laboratory testing [serum Ca and P, creatinine and parathormone levels (PTH)] which led to the diagnosis of P-HPT had been performed, the size and weight of the parathyroid glands measured, and postoperative serum PTH levels determined. Paraffin-embedded parathyroid tissue specimens were stained with antibodies to IGF-1, VEGF, and TGF-beta 1 using standard immunohistochemical procedures. Results: IGF-1 immunoreactivity was seen in 50% of hyperplasia and in 46% of adenoma samples, but in 87% of normal parathyroid tissue in the vicinity of the adenomas (P = 0.005). TGF-beta 1 immunoreactivity was observed in 90% of hyperplasia, in 92% of adenoma samples, and in 95% of normal tissues around adenomas. VEGF immunoreactivity was observed in 70% of hyperplastic and 65% of adenomatous tissues, as well as in 54% of normal tissues in the vicinity of the adenoma. No significant differences in the expression of IGF-1, TGF-beta 1, and VEGF were observed between primary adenomas compared to hyperplasia samples (P > 0.05). Conclusions: Parathyroid tissue is clearly a site for production of IGF-1, TGF-beta 1, and VEGF. IGF-1 receptor activity was higher in normal parathyroid tissue compared to hyperplastic and adenomatous tissue.