Figure 6. Phosphorylation at Ser668 promotes angiogenesis, proliferation, and tumor growth in vivo. One million (A) RKO (WT, n = 7; 668E, n = 9) and (B) HCT116 (n = 10 for both groups) cells stably expressing WT or 668E were injected subcutaneously into the rear flanks of athymic nude mice. Tumor volumes were monitored over time by caliper measurements (graphs). At the end of the study, RKO tumors were harvested and immunostained with antibodies specific for (C) Ki67 and (D) CD34 to assess proliferation and angiogenesis, respectively. Percent Ki67 and vessel count were determined as described in the materials and methods section. *P < 0.05.