Disruption of baseline as well as ligand-stimulated HER2-HER3 and HER2-EGFR dimerization has been documented upon pertuzumab treatment of HER2-positive SKBR3 breast cancer cells or MCF7 breast cancer cells, which express wild-type (nonamplified) levels of HER2 [148]. This evidence concerns the gene EGFR and breast cancer.