While many cancer-specific alterations in PcG subunits are related to specific developmental pathways or cancer-specific phenotypes, some sets of paralogs are universally up and downregulated across multiple cancers, including EZH2/EZH1, RING1B/RING1A and (CBX2/CBX8)/(CBX6/CBX7) (Figure 4). Here, RING1 is linked to cancer.