KDR and neoplasm: This is illustrated by the black arrowheads in Figure 3C and D. The large tumor cells (Fig. 3C) and large tEC (Fig. 3D) are represented by only one population of cells expressing low levels of VEGFRs, which is illustrated by the gray arrowheads in Figure 3C and D. These characteristics are shared across weeks 3 and 6 tumor cells and tEC labeled with VEGFR1 and VEGFR2.