These two differentially spliced exons (2a and 2b) which have bona-fide consensus splice sites at their ends had their expression confirmed by RT-PCR amplification using novel exon specific primers Amplification of PCA3 using the PCA3-4F primer together with a primer corresponding to exon 2a detected 5/8 PCa and 4/8 metastatic samples and again provided excellent discrimination with BPH (Fig 1D). Here, PCA3 is linked to benign prostatic hyperplasia.