WW domain-binding protein 2, encoded by the WBP2 gene, is a breast cancer oncogene.20, 21 WBP2 serves as a molecular on/off switch that controls the crosstalk between ERα,22 WWOX,23 Wnt24 and Hippo signalling networks.25 As a co-activator of ER, WBP2 binds to ERα directly and activates proliferation-related target genes expression to promote the pathogenesis and progression of breast cancer.24 As described above, ERα is critical for chemotherapy resistance in breast cancer. This evidence concerns the gene ESR1 and breast carcinoma.