ERBB2 and breast cancer: We then analyzed the expression of epidermal growth factor receptors 1 and 2 (EGFR, HER2) in BLECs, hCMEC/D3 and two breast cancer cell lines: BT 474 (HER2-positive breast cancer cell line) and HC 1806 (triple-negative breast cancer cell line) (Figures 1C,D).