RWPE-1 and three PCa cell lines were cultured and then three ERG siRNAs were used to transfect these cells one by one in order to select the optimal ERG siRNA for subsequent studies, including siRNA-ERG-582 (Forward: 5'- GACGUCAACAUCUUGUUAUTT-3'; Revise: 5'-AUAACAAGAUGUUGACGUCTT-3', siR-E-582), siRNA-ERG-834 (Forward: 5'-CCUGAAGCUACGCAAAGAATT-3'; Revise: 5'-UUCUUUGCGUAGCUUCAGGTT-3', siR-E-834) and siRNA-ERG-1183 (Forward: 5'-GGAAGAGCAAACCCAACAUTT-3'; Revise: 5'-AUGUUGGGUUUGCUCUUCCTT-3', siR-E-1183). The gene discussed is ERG; the disease is posterior cortical atrophy.