Environmental factors affecting the risk of breast cancer and the modulating role of vitamin D on this malignancy

Breast cancer is the most common type of cancer in women worldwide and is the second leading cause of cancer-related death in women after lung cancer. The disease is affected by factors such as the genetic structure of hormonal profiles and different lifestyles. Geographical status, living status, age of marriage, obesity, and nutritional factors are among the environmental factors predisposing to breast cancer. Among dietary supplements, the protective effect of vitamin D on breast cancer has been confirmed. The inverse relationship between sun exposure and breast cancer mortality has been proven. The direct link between decreased serum vitamin D and an increased risk of breast cancer has also been confirmed. In some breast cancer cells, the active form of vitamin D increases the expression of adhesion molecules, which prevents cancer from invasion and metastasis. In addition, this active form has anti-angiogenic activity and can inhibit cancer cell invasion. In this review, we narrate the environmental factors affecting the risk of breast cancer and the modulating role of vitamin D in this malignancy.