The role of vitamin D in breast cancer

The biological role of vitamin D outside of calcium homeostasis is still under evaluation. The ability of vitamin D to inhibit cell proliferation and induce differentiation makes it a potential modifier of neoplastic transformation. Vitamin D affects the cell cycle, apoptosis, hormone receptors, angiogenesis, and hypoxia, all of which are related to the breast cancer growth, progression and metastasis. A large percentage of the industrial-world population is deficient in vitamin D. Epidemiological evidence suggests that vitamin D deficiency increases the risk of breast cancer. Vitamin D may have synergistic, additive, or antagonistic effects when combined with other therapeutic agents against breast cancer. Vitamin D appears to depress aromatase inhibitor by acting through cytochrome P 450. This evidence along with pre-clinical and clinical studies, justify the inclusion of vitamin D in future clinical trials related to breast cancer in order to determine its efficacy as a part of the breast cancer therapeutic armament.