Compared with the vehicle group (n = 7 from 5 mice), the residual cetuximab-treated HNSCC (n = 9 from 6 mice) showed downregulated HIF-1α, Hes1, EGFR, and CD31 expression (P < 0.001, Fig. 7A with quantification in Fig. 7B). This evidence concerns the gene PECAM1 and head and neck squamous cell carcinoma.