First, to evaluate whether the biological activity of EVOO polyphenols in terms of cell viability not only related to HER2 protein overexpression but further required an enhanced tyrosine kinase activity of HER2 as a molecular "hallmark" in EVOO polyphenols-sensitive breast cancer cells, we used a pharmacological approach to determine the effect of "HER2 activity-dose" on the tumoricidal effects of EVOO polyphenols. The gene discussed is ERBB2; the disease is breast cancer.