Interestingly, while we were able to confirm PDE4D7 overexpression in ERG positive PCa samples, PDE4D1/2 and PDE4D9 seemed unaffected by ERG, whereas PDE4D5 expression was altered significantly in two out of five datasets, suggesting that any connection between PDE4D5 and ERG is weak at best (see Figure 3). The gene discussed is ERG; the disease is posterior cortical atrophy.