While ESRP1 downregulation promotes EMT, ESRP1 overexpression in the mesenchymal state of ovarian or breast cancer cells drives a phenotypic switching from the mesenchymal to epithelial state defined as mesenchymal–epithelial transition (MET), which is an important step for tumor formation in metastatic sites [12–14]. Here, ESRP1 is linked to breast cancer.