INTRODUCTIONrnBreast cancer is one of the most prevalent malignancies in women worldwide.1 Despite the recent advances in the development of anti-cancer therapeutic agents, the overall survival rate for patients with metastatic breast cancer remains poor, which highlights the need for more innovative and rational therapeutic strategies.2 Among the various nutraceutical agents tested for treatment of breast cancer, Vitamin D (Vit. D) showed significant promise as it decreases cell proliferation, angiogenesis, promotes cellular differentiation and apoptosis, and stimulates immune response.