Vitamin D could reduce breast cancer risk San Francisco - Arabstoday Women in the San Francisco Bay area, where there is a high level of breast cancer, are more likely to have a variant of a vitamin D receptor, researchers say. Primary study author Kathie Dalessandri, a surgeon scientist in Point Reyes Station, said the small pilot study of Marin County women at high risk for breast cancer were almost twice as likely to have a variant of a vitamin D receptor as the overall population in the study, the San Francisco Chronicle reported. Numerous studies have observed a correlation between a lack of vitamin D and a higher risk of cancer, but this is the first study linking the vitamin D receptor -- a protein molecule that signals the cell to activate vitamin D -- with higher risk for breast cancer in Marin County women, Dalessandri said. Dalessandri said Marin County has one of the highest rates of breast cancer in the world. However, the study, published online in the Journal of the American College of Surgeons, said the role of the variant in the vitamin D receptor and how that affects the amount of vitamin D in the body is unclear.