This study reveals for the first time that all the major families of EVOO polyphenols (i.e. secoiridoids and lignans) represent previously unrecognized phytochemicals that significantly affect breast cancer cell proliferation and survival through a molecular mechanism involving, at least in part, a significant down-regulation of HER2 expression and activity (Figure 14). The gene discussed is ERBB2; the disease is breast carcinoma.