Targeting tumor vasculature: sunitinib. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) (left) and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) images (right) before therapy (top) and after 1 week of sunitinib (bottom). DCE-MRI studies show gray-scale images with color-coded regional perfusion (signal enhancement ratio, or SER) superimposed. Red indicates high levels of perfusion, and blue indicates lower levels. DCE-MRI and FDG PET with kinetic analysis were used to monitor breast cancer response to neoadjuvant sunitinib and metronomic chemotherapy.