RNF2 and acute myeloid leukemia: Ring1a exerts overlapping functions with Ring1b in catalyzing H2AK119ub1.12 By cooperating with Ring1b and other PcG proteins, Ring1a regulates processes such as chromosome X inactivation,12 Hox gene silencing,17 and ES and AML stem cell identity maintenance.18–20 Although Ring1a is widely expressed in various immunocyte types, its role in the immune system and immune-related disorders remains largely unexplored.