Tumour regressions have been noted, and positron emission tomography (PET) imaging studies and a rise in serum VEGF levels parallelled by a consistent decrease in soluble VEGFR-2 levels indicate antiangiogenic activity (Manning et al, 2003; Raymond et al, 2003; Rosen et al, 2003; Toner et al, 2003). This evidence concerns the gene KDR and neoplasm.