In an observational study, the involvement of survivin, an inhibitor of apoptosis, highly expressed in mCRPC and associated with poor clinical outcome in CTCs has been suggested and the study showed that siRNA-mediated survivin-knockout inhibited EMT and invasiveness of CTCs and DU145, an AR-independent metastatic PCa cell line (23). This evidence concerns the gene BIRC5 and posterior cortical atrophy.