SLC2A3 and neoplasm: We observed that 13C-adenosine, 13C-cytidine, 13C-guanosine and 13C-uridine were dramatically reduced in HCT116 tumours with SLC2A3 silencing (Fig. 5c–f), whereas these 13C-labelled metabolites were significantly upregulated in RKO tumours with forced GLUT3 expression (Fig. 5g–j).