ERBB2 and breast cancer: Three breast cancer cell lines with transiently reduced ARHGAP29 expression were examined for their invasive abilities: HCC1806 cells, which are referred to as triple negative due to the lack of expression of progesterone and estrogen receptors and the lack of human epidermal growth factor receptor 2 (HER2) overexpression, and the two mesenchymal transformed cell lines MCF-7-EMT and T-47D-EMT.