Since high Notch1 expression associates with transition from ductal carcinoma in situ to invasive cancer, as well as worse overall survival of breast cancer patients (65), it is possible that enhanced Notch1 expression in tumor cells during their malignant progression promotes stromal secretion of CCL2 in breast cancer (Figure 2A). The gene discussed is NOTCH1; the disease is ductal breast carcinoma in situ.