KDR and neoplasm: VEGFR2 surface levels on tumors, display qualitatively different distributions at week 3 (Fig. 5B) and week 6 (Fig. 5D), but display quantitative similarity in the averages: ∼70% have 1100 surface-VEGFR2/tumor cell at week 3 and ∼50% have 1000 surface-VEGFR2/tumor cell at week 6.