In a clinical trial, a large group of post-menopausal women were given vitamin D and calcium supplements and followed to determine the effects of the treatment on the development of skin cancer. The results showed that for women at high risk of developing cancer, (those who had previously had a non-melanoma skin cancer), the treatment reduced the risk that they would develop melanoma, the skin cancer with the greatest mortality.
Learn More
Image Credit
Wikimedia Commons http://upload.wikimedia.org/wikipedia/commons/thumb/b/b3/Celestia_sun.jpg/120px-Celestia_sun.jpg