Epithelial‐mesenchymal transition has been found to be closely related to tumour invasion and metastasis.16, 17 The molecular mechanisms of EMT are complex, and various molecules have been found to regulate EMT, including miRNAs.18, 19, 20, 21 Pygo2 has been shown to promote the proliferation of breast cancer cells.22 Zhang S et al23 reported that Pygo2 promoted cell invasion and metastasis through decreasing E‐cadherin expression in hepatic carcinoma. Here, CDH1 is linked to breast cancer.