Objective: Inhibitor of differentiation (Id1) is highly expressed in head and neck squamous cell carcinoma (HNSCC). However, the role of Id1 in HNSCC is poorly understood. The purpose of this study is to determine whether Id1 regulates angiogenesis in HNSCC.
Design: Human HNSCC tissue specimens were procured for examination of the coexpression of Id1 and CD31 (an endothelial cell marker). An HNSCC cell line (CA9-22) and a nontumorigenous keratinocyte cell line (Rhek-1A) were transfected with Id1 and harvested for evaluation of vascular endothelial growth factor (VEGF) and interleukin 8 (IL-8) promoter activities. In addition, human umbilical vein endothelial cells (HUVEC) were transfected with Id1 for evaluation of cell proliferation by 5-bromo-2"-deoxyuridine incorporation and cell counts.