MTA1 and breast cancer: As a regulator of epithelial-mesenchymal transition, ZEB2 is strongly downregulated by miR-221 (Chen et al., 2010), and ZEB2 expression was increased, which in turn inhibited the expression of G9A and MTA3 by recruiting G9A/NuRD (MTA1), thereby promoting the metastasis and progression of breast cancer (Si et al., 2015).