BACKGROUND: Genes upregulated within the tumour microenvironment represent potential targets for rational drug design. Most studies to date concentrate on the effects of hypoxia, although it is likely many genes are regulated by a more physiological combination of factors. MATERIALS and METHODS: Cells under conditions analogous to the normal and tumour microenvironments were isolated from the plateau-phase system and multicellular spheroids. Gene expression was analysed by differential displa...