Although a previous study reported the upregulation of Notch-responsive gene HES1 via sonic hedgehog in multipotent mesodermal cells (Ingram et al., 2008) and co-targeting Notch and hedgehog depletes docetaxel-resistant cells in hormone refractory prostate cancer (Domingo-Domenech et al., 2012), functional interactions between these important developmental pathways have been largely unexplored in breast cancer. This evidence concerns the gene HES1 and breast cancer.