Context • Breast cancer is a leading cause of cancer fatalities among women worldwide. Of the more than 80% of patients who receive adjuvant chemotherapy, approximately 40% relapse. The majority of these patients die of disseminated metastatic disease, which emphasizes the need for new therapeutic strategies Objective • The study intended to investigate the anticancer effects of oleuropein (OL) and doxorubicin (DOX) individually and in combination on breast tumor xenografts and also to evaluate the molecular pathways involved.