RNF115 and breast cancer: Breast cancer-associated gene 2 (BCA2), an E3 SUMO ligase for IκBα in breast cancer cells, promotes IκBα SUMOylation, thereby preventing its ubiquitination for proteasomal degradation and boosting breast cancer cell proliferation and migration [122]; similarly, K379 of delta-lactoferrin (DLf), which can be either ubiquitinated or SUMOylated, is a key site for controlling DLf stability.