However, when RT-PCR was performed in prostate cancer cell lines and prostate tissues using specific primers for exons 1A and 1B, two different 3'splice sites of exon 1 were used, a and b, both presenting a consensus -AG/G sequence for U2AF65 protein binding, but lacking a clear polypyrimidine tract and branch point. This evidence concerns the gene U2AF2 and Familial prostate cancer.