Staurosporine induces neuronal differentiation and suppresses malignancy of human prostate cancer TSU-Prl cells. To investigate the mechanism underlying neuronal differentiation and suppression of malignancy, we used cDNA microarrays to examine gene expression profiles in TSU-Prl cells treated with staurosporine. mRNAs isolated from untreated and staurosporine-treated TSU-Prl cells were hybridised to microarrays consisting of similar to 9100 genes. Changes in gene expression were verified by Northern blot analysis. Staurosporine-responsive genes were involved in a variety of cellular functions including growth regulation, differentiation, replication, DNA repair, G2/M transition and inhibition of apoptosis. Interestingly, expression of genes associated with cell proliferation and malignancy, such as Cyr61 and CTGF, was reduced. Expression of CD73/NT5E, which is involved in neuronal differentiation, was increased. In the present study, we identified various staurosporine-responsive genes in TSU-Prl cells. Further studies of the roles of these genes may clarify the mechanisms underlying neuronal differentiation and inhibition of malignancy by staurosporine and identify better approaches for the prevention and treatment of prostate cancer.