The search for new and more specific molecular markers of prostatic cancers has led, in recent years, to the identification of the DD3 gene. Using reverse transcription (RT)-PCR, we investigated DD3 gene expression in human cell lines, in blood samples from healthy men and women donors and in various neoplastic and non-neoplastic tissues from the prostate and other organs. Whereas RT-PCR analysis using primers that amplified the region spanning exons 1 and 3 yielded DD3 gene expression in all samples examined, a primer downstream to exon 4 detected the expected size DD3 band only in benign and malignant prostatic tissues. These findings indicate that the only prostate specific region of DD3 is exon 4.