ERBB2 and breast cancer: We also evaluated the levels of TIMP-1 mRNA and protein in breast cancer cell lines and found that TIMP-1 expression was significantly elevated in the TNBC cell lines (MDA-MB-231, MDA-MB-468, MDA-MB-435 and BT549) compared with the luminal (MCF-7 and BT474) and HER2+ breast cancer cell lines (SK-BR-3) and the normal epithelial cell line (MCF-10A) at the mRNA and protein levels (Fig. 1c and d).