Vitamin D and Breast Cancer: Latest Evidence and Future Steps

What is it about?

Vitamin D (the sunshine vitamin) plays a vital role in calcium homeostasis, skeletal metabolism, and immune, cardiovascular, and reproductive systems’ functions. The worldwide prevalence of vitamin D deficiency is approximately 1 billion. Vitamin D deficiency is a serious health problem with numerous health consequences; it is associated with diabetes, rheumatic arthritis, Parkinson, Alzheimer diseases, osteomalacia, osteoporosis, and fractures in adults and cancers. Many reports showed an inverse association between serum vitamin D concentration and incidence of several cancers, including breast, colorectal, kidney, lung, and pancreatic. About 20 different cancers have incidence rates inversely related to solar UV-B doses and serum vitamin D concentration. Considering the rising incidence of breast cancer and high prevalence of vitamin D deficiency, this review aimed to reflect an association between serum vitamin D concentration and breast cancer risk, reveal the link between vitamin D receptor genetic polymorphisms and breast cancer risk, and review the relationship between vitamin D level, breast cancer risk, and prognostic factors such as tumor stage, grade, size, lymph node involvement, and hormone receptor status.

Featured Image

Why is it important?

the vitamin D studies support the inverse association between vitamin D level and breast can-cer risk, and retrospective and prospective epidemiologic stud-ies revealed that vitamin D deficiency is associated with increased breast cancer risk. Nonetheless, there is an urgent need for better designed and randomized clinical trials that will address the association of vitamin D level with breast cancer risk, breast cancer development, recurrence, and survival at dif-ferent breast cancer stages. These trials can be developed according to the model by Grant and Boucher23 for designing and analyzing vitamin D RCT with application to cancer inci-dence. Input variables will be vitamin D dose, baseline and achieved 25(OH)D concentrations, known rates of cancer for the population, and numbers of participants for the treatment. These studies should be applied to different population eth-nicities, for pre- and postmenopausal women, with VDR polymorphism screening. The lifestyle, dietary factors, and gene variants of other genes that influence vitamin D path-ways, such as vitamin D–binding proteins, and the enzymes that involve in vitamin D activation, such as CYP2R1, CYP27A1, CYP27B1, and CYP24A1, should also be taken into account.

Perspectives