[Coexpression of VEGF and bFGF is associated with increased vascular density in head and neck carcinomas]

Angiogenesis is crucial for tumor growth and metastasis. In several tumors, microvascular density has been shown to correlate with metastasis and aggressiveness. Vascular endothelial growth factor (VEGF) and basic Fibroblast Growth Factor (bFGF) are known to have potent angiogenic activity. Their expression has been identified in a wide variety of malignancies including head and neck squamous cell carcinoma (HNSCC). Aim of our study was to investigate the role of co-expression of VEGF and bFGF for angiogenesis in HNSCC.

Cryostat sections of 51 primary HNSCC were immunostained for VEGF and bFGF using a standard streptavidin-biotin complex procedure. To evaluate angiogenesis, endothelial cells were stained immunohistochemically using anti-vWF polyclonal antibody. Microvessels were quantified by counting vessels in a x200 field in the most vascular area of the tumor.

25/51 (49%) of the investigated carcinomas showed co-expression of both factors (VEGF+/bFGF+), while 6/51 (11.7%) carcinomas only expressed VEGF and 13/51 (25.5%) carcinomas expressed bFGF. 7/51 (13.7%) tumors showed no expression of these factors (VEGF-/bFGF-). Carcinomas with a co-expression of VEGF and bFGF showed a significantly increased mean microvessel density (88.3 +/- 24.4) compared to tumors expressing only VEGF (77 +/- 16.8) or bFGF (71.1 +/- 15.8) (p = 0.022) or tumors with no expression of both factors (51.1 +/- 13.4) (p < 0.001). The association of VEGF and bFGF expression level was not significant (p = 0.178).

The positive correlation of the co-expression of angiogenic VEGF and bFGF with increased microvessel density underlines the importance of both factors for tumor angiogenesis in HNSCC. VEGF and bFGF might act cooperatively in the process of neovascularization in human head and neck cancer.