Expression of basic fibroblast growth factor protein and its down-regulation by interferons in head and neck cancer

Background. Angiogenesis is crucial for tumor growth and metastasis. In sev eral tumors, microvascular density has been shown to correlate with metasta sis and aggressiveness. Basic fibroblast growth factor (bFGF) has potent an giogenic activity and has been identified in a wide variety of malignancies including head and neck squamous cell carcinomas (HNSCC). Material and Methods. Frozen sections of 50 HNSCC were immunostained for von Willebrand factor and bFGF. Microves sets were counted by light microscopy; bFGF expre ssion was studied at the light and electron microscopic level. Laryngeal ca ncer cell line HlaC79 was incubated with interferon (IFN) alpha and beta. b FGF quantification was performed by ELISA, and antiproliferative effects we re determined by BrdU assay. Results. The mean number of blood vessels (77.5 +/- 23.7) is significantly increased in HNSCC compared with controls (17.1 +/- 5.9). bFGF protein expr ession was detected in all HNSCC but not in control tissue. An correlation between bFGF expression and mean number of microvessels was found (p < .001 ). However, no correlation between bFGF expression and the main clinicopath ologic features was shown. The long-term exposure (144 hr) of HNSCC cells t o noncytostatic concentrations of IFN alpha and beta (>10 U/mL) down-regula ted the protein production of bFGF. Conclusion. bFGF expression and angiogenesis are enhanced in HNSCC. The hig her microvessel density in HNSCC with strong bFGF expression supports the i mportance of bFGF for tumor angiogenesis. IFN alpha and beta treatment lead s to a downregulation of bFGF expression independent of their antiprolifera tive effects, suggesting that IFN treatment might result in a reduction of angiogenesis in HNSCC. (C) 2000 John Wiley & Sons, Inc.