CTCF and posterior cortical atrophy: We determined that the loop regions anchored by the two PCa risk-associated CTCF sites (site 1 on chr1 and site 4 on chr12) are both covered by H3K27me3, which is known to be associated with polycomb-mediated gene silencing [33]; deletion of the risk-associated CTCF sites may result in the formation of new enhancers within these previously repressed regions.