Calcium, vitamin D and the vitamin D receptor: impact on prostate and breast cancer in preclinical models.

Epidemiological, molecular, and cellular studies have implicated vitamin D, a fat-soluble vitamin, and the vitamin D receptor (VDR) in the development and/or progression of cancer. The activation of vitamin D in the kidney is intricately linked to dietary calcium, another nutrient that has been associated with cancer risk in epidemiological studies. While calcium and vitamin D interact in the maintenance of skeletal health, it is now recognized that these nutrients exert independent effects on cell behavior, including proliferation, differentiation, and apoptosis. In addition to the kidney, many tissues contain VDR and express vitamin D-metabolizing enzymes. The regulation of these enzymes is likely tissue specific and unrelated to calcium status. This short review will focus on data generated from animal, cell, and molecular studies that have assessed the interactions between calcium and vitamin D on breast and prostate cancer.