CBX2 and cancer: Prior work suggests a role for CBX2 overexpression in driving PrCa metastasis that was reversible upon siRNA inhibition of CBX2. 21 Metastatic cancer cells undergo reversible changes during the complex processes of extravasation, infiltration, seeding and proliferation within distant sites, and members of the polycomb complex, such as EZH2, have been associated with metastasis and invasion.41,42 This apparent plasticity is likely to be governed by epigenetic processes, as opposed to DNA sequence mutations.