In this study, cDNA microarrays were used to characterize gene expression changes elicited in prostate cancer cells by plating them on type I collagen. The results clearly reveal changes in the expression of genes associated with cellular signaling, cellular metabolism, gene transcription and gene translation which are indicative of cells that are actively proliferating. Together these results suggest that these changes in the gene expression profiles mediated by type I collagen may influence the proliferative capacity of prostate cancer cells in the bone microenvironment and facilitate development of prostate cancer bone metastases. Additionally, the microarray approach provides an invaluable tool to determine and track changes in gene expression in numerous disease states including prostate cancer. This technology is certain to facilitate discovery of new therapeutic gene targets.