Estrogen effects on transmigration activity were tested on human and murine brain vascular endothelial cells by measuring the passage of low-metastatic (MCF-7), Her2+ (BT-474), and TN (MDA-MB-231) BC cell lines using a microplate reader to calculate the difference in fluorescence signal with and without E2 and DPN treatment in the concentrations 10−12, 10−10, and 10−8 M. Here, ERBB2 is linked to breast cancer.