Fibroblast Growth Factor–like Autoantibodies in Plasma from Patients with Multiple Endocrine Neoplasia Type 1 and Prolactinoma

Multiple endocrine neoplasia type 1 (MEN1) is characterized by hyperfunction and growth of the parathyroid, pancreatic islet, and anterior pituitary glands. We previously reported increased basic fibroblast growth factor (bFGF) immunoreactivity and bFGF-like bioactivity in plasma from patients with MEN1.I Because bFGF is not readily detectable in plasma from normal subjects, we tested the hypothesis that some bFGF-like activity in plasma from MEN1 and sporadic pituitary tumor subjects corresponds to an immunoglobulin that mimics bFGE