Glucose metabolism. A, Intratumoral distribution of [18F]FDG-derived radioactivity in tumour sections (FGF8b n = 6, VEGF n = 6 and mock n = 5). Uptake intensity is not comparable between these images, since they were not corrected for injected dose or cross-calibrated between separate studies. B, Tumour-to-blood (T/B) uptake ratio of [18F]FDG (T/B ratio) in FGF8b (n = 6), VEGF (n = 6) and mock (n = 5) tumours is expressed as mean ± SD. The accumulation of [18F]FDG was significantly lower (p < 0.05) in FGF8b tumours compared with VEGF and mock tumours. Number of cells/cm3 was determined using TrueCount tubes and flow cytometry. On the right, we show relative uptake of [18F]FDG after balancing the uptake against cell number. C, Immunostaining of the glucose transporter GLUT1 showed decreased staining in VEGF tumours compared with mock and FGF8b tumours (FGF8b n = 5, VEGF n = 4 and mock n = 7 tumours) (p < 0.05 VEGF vs. mock, Bar 200 μm). Analysis was carried out in a blinded manner in three representative non-overlapping fields of the tumours, and the data presented as mean ± SD.