Objective: It is widely recognized that the insulinlike growth factor (IGF) system is involved in cancer progression and tumorigenesis. To determine the contributions of this system in head and neck squamous cell carcinoma (HNSCC), we examined patient samples and established HNSCC cell lines for IGF system expression and activity.
Design: The HNSCC patient tumor/normal matched pair samples were assessed for IGF-1 receptor (IGF-1R) and IGF binding protein (IGFBP) expression by immunoblot analysis. Eight HNSCC cell lines were assayed for IGF-1, IGF-2, IGFBP, and IGF-1R expression. IGF-1–stimulated Erk and Akt activation was evaluated in the context of vascular endothelial growth factor (VEGF) secretion and cell proliferation. The VEGF was quantified in conditioned medium by immunoblot analysis and cell proliferation was assessed by flow cytometry.