FZD1 and breast cancer: Another example is MBD2, a DNA methylation binding protein with two different splice variants MBD2a and MBD2c, which has opposite effects on breast cancer metastasis: MBD2a promotes tumor metastasis by enhancing FZD1 gene expression to activate the Wnt/β-catenin pathway and epithelial-mesenchymal transition (EMT); tumor metastasis is impeded by MBD2c by competitively inhibiting the effect of MBD2a on FZD1 gene (56).