RNF20 and cancer: These results extend to human cancer cells previous findings on the role of H2Bub (H2BK123ub) and Bre1 (RNF20 homolog) in yeast, where H2Bub was reported to facilitate replication fork stalling during replication stress (Hung et al, 2017; Lin et al, 2014; Northam and Trujillo, 2016).