KDR and neoplasm: In a multi-institutional phase I/II study of erlotinib plus bevacizumab for recurrent or metastatic squamous cell carcinoma of the head and neck, higher ratios of tumor cell pVEGFR2 to total VEGFR2 and higher ratios of endothelial cell pEGFR to total EGFR in pretreatment biopsy samples were associated with complete response and tumor shrinkage [29].