THE EXPRESSION AND LOCALIZATION OF FIBROBLAST GROWTH-FACTOR-I (FGF-1)AND FGF RECEPTOR-1 (FGFR-1) IN HUMAN BREAST-CANCER

Fibroblast growth factor-1 (FGF-1) is an inducer of angiogenesis, the growth of new blood vessels. The expression and localization of FGF-1 (acidic FGF) and FGF receptor (FGFR)-1 in mammary tissues from patient s with breast cancer was investigated using Western blot analysis and immunohistochemistry. The affinity-purified FGF-1 antibody which did n ot have cross-reactivity to FGF-2 (basic FGF) was used in this study, Western blot analysis demonstrated the presence of FGF-1 protein in al l of the samples from breast cancer, but not benign tumors such as mas topathy and fibroadenoma. To assess the localization of FGF-1 in cance r tissues, immunostaining with specific antibody was performed. AU sam ples from breast cancer displayed significantly intense staining with FGF-1 antibody. The extent and intensity of immunoreactive FGF-1 polyp eptides in cancer cells was statistically much greater than those of c ells from fibroademoma or mastopathy. Control immunostaining with norm al rabbit serum or anti-FGF-1 antibody adsorbed with the recombinant F GF-1 polypeptide was completely negative. In contrast to PGF-1, Wester n blot analysis demonstrated the presence of FGFR-1 protein in all of the samples from breast cancer and benign tumors. By immunohistochemic al analysis, the enhanced expression of FGFR-1 was observed in breast cancer cells. Benign tumor cells or interstitial cells displayed a fai nt expression of FGFR-1. These results demonstrated that breast cancer cells not only generated FGF-1, but also expressed FGFR-1, and FGF-1 might play a role in the proliferation of breast cancer cells not only by paracrine but also by autocrine mechanism. (C) 1998 Academic Press .