CUL4B and breast carcinoma: Moreover, Snail is directly transcriptional repressed by MTA3[18] and ZEB2 represses MTA3 expression through the formation of a ZEB2/G9A/NuRD(MTA1) complex.[20] Evidently, a reciprocal feedback regulatory loop exists during breast cancer progression in which loss‐of‐function of ERα and GATA3 leads to elevated expression of CUL4B and MTA1.