KDR and neoplasm: That blocking the VEGF-VEGFR-2 pathway may inhibit tumor growth is exemplified in studies using neutralizing KDR/Flk-1 mAb[25], KDR/Flk-1 kinase inhibitors[26,27], or a dominant-negative Flk-1 receptor[28], all of which were shown to inhibit angiogenesis and tumor growth.