To investigate whether we could disrupt pre-mRNA splicing of the ERG oncogene in the context of prostate cancer (PCa), we first designed SSOs targeting the 3′ (E43′) and 5′ (E45′) splice-sites of exon 4 of ERG (Fig. 1a, Supplementary Fig. 1a). The gene discussed is ERG; the disease is prostate cancer.