UBE2I and breast carcinoma: DNA damage induces nuclear accumulation of the small ubiquitin-related modifier (SUMO) E2 ligase, ubiquitin conjugating enzyme E2 I/ubiquitin conjugating enzyme 9 (UBE2I/UBC9) in human MDA-MB-231 and MCF-7 breast cancer cell lines (Li et al., 2019).