TCF4 and cancer: These insights are of significance and have clinical and therapeutic potential as our findings add FMOD to the list of β-catenin/TCF4 target genes, unveil a model by which aberrant Wnt/β-catenin signaling is involved in breast cancer progression, and indicate FMOD as well as HDAC6 as new potential targets and biomarkers for breast cancer therapy, which in turn could help guide the development and use of Aspirin as a cancer therapeutic.