Angiogenesis is a crucial step in tumor growth and metastasis. Clinical association of tumor vascularity with tumor aggressiveness has been clearly demonstrated in a wide variety of tumor types including head and neck squamous cell carcinoma (HNSCC) . Thus, determination of microvessel density in tumor tissue can be useful in estimation of prognosis. Inhibition of angiogenesis can repress the growth rate of tumor cells, and also induce apoptosis due to reduced nutrition and oxygen supply to the tumors. Vascular endothelial growth factor (VEGF), which is a major element for many angiogenic processes, binds VEGF receptor (VEGFR) to stimulate endothelial cell proliferation and migration [2,3]. Thus, determination of microvessel density in tumor tissue can be useful as a predictive factor for the effectiveness of bevacizumab in chemoradiotherapeutic strategies.