The effects of insulin-like growth factor-1 (IGF-I) on gene expression in CCL-171 fibroblasts and MCF-7 tumour cells. Unsupervised hierarchical clustering of genes deregulated in CCL-171 and MCF-7 cells upon IGF-I stimulation. The gene expression levels were normalized to the non-stimulated specimens as described. Genes are presented in rows and experiments in columns. The red and green colours provide information about up- or down-regulation, respectively. The intensity of the colour renders quantitative information about the change in expression level. IGF-I stimulation induces some common and some distinct effects on the gene expression profiles in different cell types. (A) Genes specifically up-regulated in MCF-7 cells involved in: epidermal growth factor and fibroblast growth factor signalling; protein metabolism and modification; nucleoside, nucleotide and nucleic acid metabolism. (B) Genes specifically up-regulated in CCL-171 cells include transcription factors and transferases, in addition to genes involved in Wnt and TGF-β signalling.