Vascular endothelial growth factor is a marker of tumor invasion and metastasis in squamous cell carcinomas of the head and neck

Angiogenesis has been linked to increased metastasis formation and decrease d overall survival in patients with various tumors, including and neck squa mous cell carcinomas (HNSCC). Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis, In the present study, we evaluated VEGF ex pression and microvessel density (MVD), a quantitative means of angiogenesi s, in both experimental and clinical models of HNSCC. Analysis of VEGF RNA expression in cell lines of keratinocyte origin [HNSCC, falcial skin squamo us cell carcinoma (SCC), and transformed but nontumorigenic keratinocytes] and normal skin keratinocytes revealed two VEGF transcripts corresponding t o proteins of 165 and 121 amino acids in length, with the transcript for th e 165-amino acid species predominating. Six of eight SCC cell lines showed increased levels of one or both transcripts, and seven SCC cell lines and t he transformed keratinocyte cell line showed increased protein expression. We then evaluated VEGF protein expression in human head and neck specimens containing normal epithelium (n = 10), dysplasia or carcinoma in situ (CIS; n = 15), early invasive SCCs (n = 9), advanced primary SCCs (n = 10), lymp h node metastases (n = 3), and s.c. tumors or cysts (n = 7) formed in sever e combined immunodeficient mice. Intense VEGF staining was found in the maj ority of advanced primary SCCs, lymph node metastases, and human SCCs in se vere combined immunodeficient mice, whereas no dysplasia, CIS, or early SCC s showed intense immunostain, A highly significant increase (P = 0.0001) in VEGF expression was seen in the advanced SCC versus dysplasias and CIS les ions, as was the difference between SCC versus normal epithelium from nonsm okers (P = 0.01). VEGF expression in advanced primary cancers was greater ( P = 0.002) and, in early cancers, marginally greater (P = 0.05) than adjace nt normal mucosa, MVD increased with the progression of preinvasive disease (P = 0.04). VEGF expression and MVD (both, P = 0.003) were directly associ ated with tumor aggressiveness in experimental tumors. These findings sugge st a role for VEGF in both clinical and experimental HNSCC.