Figure 4.

GTPCH overexpression and BH4 synthesis promote angiogenesis and tumor formation in mice. GCHtet-off cells (1 × 10⁷) were injected s.c. into flanks of 6- to 8-week-old female BALB/c SCID mice (n = 5) and Tet-off-EV as control. Tumor volumes were monitored two to three times per week (A), when they reached to maximum permitted volumes, mice were sacrificed, and tumors were sectioned and stained immunohistochemically for HA-GTPCH (red arrow-tumor cells) (A), Ki-67 (B), and CD34 (C) at × 20 magnification. Data are shown as the mean of five sections per animal ± SEM (*P < 0.05 vs. Tet-off-EV, n = 5) (ANOVA).