ERBB2 and breast cancer: To address the impact of ErbB signalling on cell invasion, we used a panel of human breast cancer cell models overexpressing exogenous ErbB2 (MCF7 and MDA231), endogenous ErbB2 (SKBR3 and T47D), or MDA231 cell variant (MDA231-M) selected in vivo from a metastatic lung nodule induced by MDA231-ErbB2 cells after implantation into the mammary fat pad.