TGF-β-induced migration of MDA-MB-231 cells is inhibited by USP4 knockdown and PI (3) K–AKT signalling inhibitors, indicating that phosphorylation of USP4 plays a critical role in AKT-mediated breast cancer cell migration (Zhang et al., 2014; Wang W. et al., 2020). Here, TGFB1 is linked to breast carcinoma.