Identification of basic fibroblast growth factor in papillary carcinoma of the thyroid

Basic fibroblast growth factor (bFGF) was identified in the papillary carcinoma of the human thyroid. Immunohistochemically, it was found that the reactivity for bFGF was localized in the cytoplasm of the neoplastic cells of the five papillary carcinomas. However the extract of the papillary carcinomas contained the mitogenic activity for endothelial cells. This bioactive molecule was determined as bFGF by using the heparin-Sepharose affinity chromatography and western blot analysis. The bFGF derived from human thyroid papillary carcinoma and the recombinant human bFGF stimulated the bromodeoxyuridine incorporation by the cultured human thyroid papillary carcinoma cells. These cells also showed positive staining for thyroglobulin and cytokeratin. These results indicate that bFGF, probably produced by the neoplastic cells, plays an important role in the development of papillary carcinoma of the thyroid with stimulation of angiogenesis as well as proliferation of the parenchymal cells.