Hydroxytyrosol, a component of olive oil for breast cancer prevention in women at high risk of cancer

This study evaluates the effects of hydroxytyrosol (HT), a component of olive oil, on mammographic breast density reduction. We explored effects of HT on Wnt β-catenin and other pathways involved in cancer stem cell renewal, DNA repair, cell proliferation and differentiation. Hydroxytyrosol reduced breast density only in women over 60 years, especially in those with high baseline breast density. HT also reduced proliferation and affected Wnt signaling pathway. This study lays the foundation for future larger studies in exploring a natural compound with well tolerability and overall nontoxic profile for chemoprevention of breast cancer. The trial was preregistered at http://clinicaltrials.gov/ (NCT02068092). 25mg/day oral dose of HT were given for 12 months in pre- and post-menopausal women at increased risk of breast cancer. Out of 51 patients enrolled, 41 completed the study. The annualized percent decrease in maximum mammographic volumetric breast density (Max VBD%) between baseline (BL) and end-of-treatment (EOT) was analyzed. RNA sequencing (RNA-Seq) and multiplex analysis was performed on the breast biopsies to compare the BL with EOT samples.