To explore this, we examined the cell surface molecules that can transduce the intercellular communication signals between cancer cells and stromal cells.<h4>Results</h4>Among these molecules, EphA3 and EphA7 receptors and their ligand ephrin-A5 were found to be expressed in prostate cancer cells, but not in prostate stromal cells. This evidence concerns the gene EFNA5 and Familial prostate cancer.