IMMUNOCYTOCHEMICAL LOCALIZATION OF FIBROBLAST GROWTH-FACTOR-I (FGF-1)AND FGF-2 IN ORAL SQUAMOUS-CELL CARCINOMA (SCC)

The localization of fibroblast growth factor-1 (FGF-1) and FGF-2 in hu man oral squamous cell carcinoma (SCC) was examined by immunohistochem ical techniques using anti-FGF-1 and anti-FGF-2 monoclonal antibodies. Immunofluorescence staining of two oral SCC cell lines revealed that growing cancer cells were intensely positive for both FGF-1 and FGF-2, but confluent cells showed a faint immunostaining. In addition, two m olecular mass species of FGF-1 (16 and Is kDa) and one of FGF-2 (18 kD a) were identified by Western blot in cell extracts derived from growi ng SCC cells, but not from confluent SCC cells. The growing cell extra cts significantly stimulated the proliferation of human umbilical vein endothelial cells. Immunoperoxidase staining of 13 oral SCC cases sho wed that both well-differentiated and poorly-differentiated cancer cel ls were positive for FGF-I and FGF-2 with high frequency and intensity as compared to normal oral epithelium. These results indicate that SC C cells express high levels of endogenous FGF-1 and FGF-2, and suggest that these growth factors may contribute to cancer cell growth.