New vessel formation in peritumoral area of squamous cell carcinoma of the head and neck.

Background: This study was conducted to investigate the dynamic process of new vessel formation, fundamental for tumor growth and metastasis, in head and neck squamous cell carcinoma (HNSCC).

Methods: We used immunohistochemistry, confocal laser-scanning microscopy, and reverse transcriptase-polymerase chain reaction to study endothelial cell and concomitant pericyte development with markers CD133, CD34, VEGFR-2, CD31, vWF, and STRO-1 in tumor and peritumoral tissues of 18 patients with HNSCC.

Results: Highly compressed and structurally abnormal vessels with barely any activity of new vessel formation were found in tumor tissue, whereas the adjacent peritumoral tissue vessels showed a normal architecture with tight endothelial cell-pericyte interaction and a high activity of angiogenesis. Endothelial precursor cells expressing CD133/VEGFR-2 could be incorporated into these newly formed vessels, forming cell clusters from which a thin endothelial lining could emanate.

Conclusions: These data show a high activity of new vessel formation in the peritumoral stroma of HNSCC, with endothelial precursor cells being incorporated into these structures.