**8. Conclusion**

This chapter concluded that women with breast cancer are more likely to have low vitamin D levels. Those women who do not get adequate vitamin D may be more likely to develop breast cancer later in life as compared to those who have higher vitamin D levels, who are less likely to develop breast cancer and less likely to die from breast cancer.

Because of the broad spectrum of vitamin D effects on mammary tissue, it is suggested to be a most important physiological growth regulator of mammary gland and could be a potential therapeutic agent. Additionally, due to the expression of VDR to a higher extent on breast epithelial cells, vitamin D signalling should also be monitored during breast cancer treatment. Since breast cancer is a complex disease which may or may not be associated with the decreased vitamin D levels or VDR polymorphisms. However, the functions and role of vitamin D and VDR cannot be neglected during breast cancer treatment.
