Promoting differentiation of luminal A breast cancer cells by targeting Notch4 signaling may be an attractive target given Notch4-restricted expression in normal tissue.46 Development of selective monoclonal antibodies and/or potential use of luteolin, recently shown to inhibit Notch4 signaling47 should be considered for future treatment of recurring and/or endocrine-resistant breast disease. This evidence concerns the gene NOTCH4 and breast cancer.