In order to determine the level of expression of different Cx isoforms and to assess whether their expression have any relationship with the degree of aggressiveness of PCa cell lines, qRT-PCR analyses were performed to measure the relative amount of Cx26, Cx32, Cx37, Cx40, Cx43 and Cx45 mRNAs in four cell lines with increasing degree of tumor aggressiveness, as follows: LNCaP < LNCaP-C4-2 < Du-145 < PC-3. This evidence concerns the gene GJA1 and neoplasm.