EXPRESSION OF BASIC FIBROBLAST GROWTH-FACTOR IN THYROID-DISORDERS

Morphologic and biologic studies were undertaken to clarify the biolog ic significance of basic fibroblast growth factor (bFGF) in human thyr oid neoplasms. A total of 71 malignant tumors (50 papillary carcinomas , 14 follicular carcinomas, 7 anaplastic carcinomas), 11 follicular ad enomas, 6 adenomatous goiters, and 6 Graves' disease tissues were exam ined employing immunohistochemical methods (avidin-biotin-peroxidase c omplex technique). An affinity-purified polyclonal rabbit antiserum to human bFGF was used as a primary antibody. The eluate of malignant th yroid tumor tissues from the heparin-Sepharose column was examined by Western blot analysis to elucidate the molecular weight form. With imm unohistochemical staining, bFGF was frequently detected in the cytopla sm of malignant thyroid tumors compared to tissues of the benign disea ses and normal controls. With anaplastic carcinoma, immunoreactivity o f the tumor cells was particularly strong. In the correlative analyses between UICC TNM classification and bFGF staining in papillary carcin oma, there were significant differences when relating positive stainin g to the grade of nodal metastases. By Western blot analysis, the bFGF immunoreactivity was specifically detected in the two forms, with mol ecular weights of 18 and 33 kDa. The high-molecular weight form was de tected in only anaplastic carcinoma. The present investigations demons trated a close correlation between the expression of bFGF and the degr ee of malignancy. bFGF might play an important role in promoting lymph node metastases. Moreover, the high-molecular-weight form of bFGF mig ht have an intense influence on tumor growth.