Expression of Vascular Endothelial Growth Factor Family Members in Head and Neck Squamous Cell Carcinoma Correlates with Lymph Node Metastasis

Background: The expression of vascular endothelial growth factor (VEGF)-A isoforms (121, 165, 189, 206), VEGF-B, VEGF-C and VEGF-D in both experimental and clinical models of head and neck squamous cell carcinoma (HNSCC) was determined and correlated with conventional clinicopathologic parameters, with particular reference to cervical nodal metastasis.

Methods: The mRNA expression of VEGFs in 14 HNSCC cell lines was compared with 4 normal keratinocyte cultures and 10 fibroblast cultures using a semiquantitative reverse transcription polymerase chain reaction (RT-PCR) assay. Protein levels were determined by Western blotting and enzyme-linked immunosorbent assay (ELISA). The authors then examined the expression of VEGFs in tissues from 54 patients including histologically normal epithelium (n = 32), early invasive squamous cell carcinomas (SCCs) (n = 23), advanced primary SCCs (n = 31), and lymph node metastases (n = 27).

Results: Increased levels of VEGF-A (all four isoforms) and VEGF-C were found in tumor cell lines compared with normal cells, whereas no differences in VEGF-B levels were found. VEGF-D expression, however, was lower in HNSCC cells. Studies in clinical samples showed highly significant increases in mRNA expression of all four isoforms of VEGF-A and VEGF-C in tumors versus normal epithelium. In contrast, the levels of VEGF-D were significantly decreased in tumors, and VEGF-B expression appeared similar in both normal and malignant tissues. Multivariate analysis demonstrated that an infiltrative mode of invasion and enhanced expression of VEGF-A (isoforms 121 and 165) and VEGF-C had predictive value for the presence of cervical nodal metastases.

Conclusions: Up-regulation of VEGF-A (two isoforms) and VEGF-C and down-regulation of VEGF-D have been common features in HNSCC. Thus VEGF-A and VEGF-C appeared to play a vital role in the metastatic process of HNSCC.