UBE2I and breast carcinoma: It was reported that ERα and NF-Y bound directly to the proximal promoter of Ubc9 and were essential for the in vivo expression of Ubc9 through transcriptional regulation (41, 56), and the overexpression of Ubc9 increased ERα-mediated transcriptional activity via enhanced SUMOylation in MCF-7 breast cancer cells, suggesting a possible synergy between Ubc9 and the promoting factor during breast cancer development (57).