ZEB1 and cancer: The LEF1 binding site CTTTGA is one of the primary binding sites in the Wnt signaling pathway which regulates cell-cell adhesion and many morphogenetic events during mammary development and possibly cancer [42,43] Binding of Wnt proteins with frizzled protein prevents degradation of β-catenin, which subsequently translocates to the nucleus and binds transcription factors of the TCF/LEF family (this includes TCF8 discussed above and LEF1).