PD0325901 inhibits the uptake of [18F]FLT in SKMEL-28 xenografts. A and B, change in [18F]FLT (A) and [18F]FDG (B) uptake in mice with established SKMEL-28 (V600E BRAF) xenografts treated with PD0325901 or vehicle only as control. Mice were treated for 3 wk on days 1 to 5 of each week. Each line represents an individual mouse treated with 25 mg/kg PD0325901 (solid blue lines) or the vehicle only (red dotted lines) imaged by [18F]FLT (A) or [18F]FDG (B) PET. Data are presented as a standard uptake value calculated using a ROI containing the tumor. C, mean values for the imaging data presented in A and B. Bars, SE. D, MEK inhibition had no effect on [18F]FLT or [18F]FDG uptake in BT-474 (HER2-amplified breast cancer, PD0325901 resistant) xenografts.