ERBB2 and breast carcinoma: pre-treatment of HER2-overexpressing breast cancer cells with the proteasome inhibitor MG-132 blocks the depletion of HER2 protein induced by EVOO polyphenols, thus suggesting that EVOO-derived lignans and secoiridoids can efficiently inhibit HER2 protein kinase activity by depleting the HER2 protein kinase itself.