In detail, those tumor cell lines with high relative malignancy, such as TNBC, MDA-MB-231 and BT549, presented lower expression levels of Notch3 and E-cadherin; conversely, the ER-positive hormone-dependent breast cancer cell lines MCF-7 and T47D presented higher expression levels of Notch3 and E-cadherin. The gene discussed is NOTCH3; the disease is breast carcinoma.