CDC73 and neoplasm: To evaluate the effects of CDC73 in UBR5-driven tumor growth, we further silenced the expression of Cdc73 in 4T1/GFP and 4T1/Ubr5−/− cells, as well as WT and UBR5 knockdown cells of MCF-7, MDA-MB-231, and BT549 by CDC73-targeted shRNAs, and the knockdown efficiency was confirmed at both mRNA and protein levels (Fig. S2).