Spotlight: Vitamin D may help in battle against breast cancer

by William G. Gilroy

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| Welsh’s research shows vitamin D can stop cancer cell growth and shrink tumors in mice ||
p. October is breast cancer awareness month. According to the National Breast Cancer Awareness campaign, an estimated 211,300 new cases of breast cancer are expected to occur among women in the United States this year. Breast cancer is the leading new cancer diagnosis for American women and is second to lung cancer as a cause of cancer death.p. Research being conducted by JoEllen Welsh, a professor of biological sciences at Notre Dame, is offering intriguing clues about the role vitamin D might play in breast cancer treatment and prevention. Studies by Welsh have indicated that vitamin D can stop the growth of cancer cells and shrink tumors in mice.p. Welsh studies genetically engineered “knockout” mice that lack the vitamin D receptor to help determine the substance’s function in breast tissue.p. “In the absence of the receptor, the mammary gland grows more than in normal mice,” she said. “This suggests that when vitamin D is present, it slows down cell growth.”p. Welsh and her colleagues also are studying mice with breast tumors treated with drugs that activate vitamin D receptors.p. “Treating cells with activators of the vitamin D receptor stops the growth of breast cancer cells and makes them undergo apoptosis, or cell death,” she said.p. Because high doses of vitamin D can be toxic, several pharmaceutical companies have asked Welsh to search for less toxic synthetic analogs of vitamin D.p. Ironically, concerns over the role that sun exposure plays in skin cancer could be leading to vitamin D deficiencies that may play a role in cancer and other diseases.p. “Sun exposure is an important source of vitamin D, which is produced when UV rays interact with chemicals in the skin,” Welsh said.p. Vitamin D deficiency is a particular concern for those living in the Northern Hemisphere, where opportunities for exposure to sunlight are limited in the winter. Welsh, who is presenting her data this month at a conference on vitamin D deficiency sponsored by the National Institutes of Health, suggests taking a multivitamin and trying to spend 15 minutes a day outdoors, without sunscreen, to combat the problem. Sunscreen blocks the body’s production of vitamin D, but short exposure of skin without sunscreen is sufficient to activate the process. Applying sunscreen after this brief exposure is important in order to minimize burning, a risk factor for skin cancer.p. Welsh’s research interests are primarily in breast cancer and vitamin D, but she points out that other studies have suggested that vitamin D also interferes with tumor growth in prostate and colon cancer.p. Welsh’s research is funded by several agencies, including the National Cancer Institute, the Susan G. Komen Foundation and the U.S. Army Breast Cancer Research Program.

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