UBE2S and cancer: Two of the E2 enzymes with a role in cancer are UbcH10 (also known as UBE2C or UBC4) and UBE2S (also called E2-EPF), both of which work with E3 ligase APC/C (Anaphase Promoting Complex/Cyclosome) in the regulation of the cell cycle.9 UbcH10 plays a role in cell cycle progression and checkpoint control.10 This protein is known to be required for APC-dependent ubiquitination of mitotic cyclins.11-13 Other E2s with a role in cancer are reviewed elsewhere.14 UBE2Q2 is a novel human gene that belongs to the UBC2 family of enzymes.