Nevertheless, when considering that the primary mechanism driving HER2 levels in human breast cancer cells is gene amplification and overexpression under the control of the endogenous promoter [44,45], the fact that EVOO polyphenols drastically decreased HER2 protein content regardless the molecular mechanism contributing to HER2 overexpression strongly suggests that EVOO polyphenols do not significantly affect the cellular transcriptional machinery that controls the endogenous HER2 locus in breast cancer cells. This evidence concerns the gene ERBB2 and breast cancer.