Genetic Variation of Vit D Receptor and Breast Cancer
Nels Johnson, The Marin Independent Journal, Novato, Calif.
Posted Aug 17, 2012
Vitamin D may provide a clue in determining why Marin County women are afflicted with one of the highest breast cancer rates in the nation, a preliminary study headed by a veteran Point Reyes Station scientist indicates.
The new study involving a small sample of Marin women suggests that a genetic trait involving a receptor that activates vitamin D may be a factor.
The Journal of the American College of Surgeons reported that University of California at San Francisco surgeon scientist Dr. Kathie Dalessandri of Point Reyes Station and colleagues, including investigators at InterGenetics Inc. of Oklahoma, discovered that cells from 338 Marin women reflect variations associated with breast cancer risk.
Dalessandri noted the findings, based on review of frozen cell samples taken from high-risk women involved in a previous Marin study, must be confirmed in a much larger study before conclusions can be drawn.
But based on the small sample, "We found that women who were at high risk for breast cancer were 1.9 times more likely to have a specific vitamin D receptor variation than the general population," she added.
The study's conclusion: "In this age of personalized genomics, it is important to consider potential genetic, environmental, and nutritional interactions with regard to sporadic breast cancer risk. Targeted vitamin D supplementation can be important because modifiable risk factors can influence prevention strategies in these higher-risk individuals."
Dalessandri had no advice on what level of vitamin D could help combat breast cancer. "It's too early to do that," she said. She noted that people process vitamin D differently -- and that "toxicity is associated with high levels" of the vitamin.
The doctor had time for a brief interview while awaiting an NBC news crew, saying the study had generated intense interest in the press -- far more than her 2004 study that indicated broccoli was a cancer fighter.
The Marin County Department of Health and Human Services oversees a pioneering, ongoing breast cancer study -- www.marinwomensstudy.org -- and mouth cell samples collected in that review were examined by university researchers in the analysis involving vitamin D. New risk-rating technology developed by Eldon Jupe of InterGenetics Inc. was used.
"If genetic variations in the vitamin D receptor prove to be causally linked to breast cancer, that may help pave the way for new ways to prevent or treat the disease through vitamin D supplementation -- though any such approaches would have to prove safe and effective in clinical trials, which can take years to reveal impact," a university report on the research said. The journal article on the vitamin study can be found at: http://dx.doi.org/10.1016/j.jamcollsurg.2012.06.413.
Researchers already have a trove of information collected in connection with the county's ongoing Marin Women's Study, which established a database focusing on health and risk factor data, genetic variables, hormone levels and mammographic breast density measurements of 14,000 Marin women.
Rochelle Ereman, head of the Marin Women's Study as well as the county's epidemiology program, said she was not surprised the new research has found a vitamin D link because "lack of vitamin D in the blood has been associated with many chronic diseases, including breast cancer." Dalessandri's research looks at "the mechanism of vitamin D -- how it processes in the body," Ereman noted.
Ereman cautioned that people should take vitamins "as recommended by their physician or health care provider."
The Marin Women's Study chief added that Dalessandri's study must be confirmed by a larger investigation. "The Marin Women's Study has been designed and is poised to assist in this larger validation study," she said. She noted data already on hand includes saliva samples from 8,500 Marin women that allows hormone study as well as genetic analysis of DNA, along with review of health histories, childbirth and breast-feeding data, environmental and personal risk factors.
The exhaustive women's study, launched after Marin's breast cancer rate topped most others in the nation, involves an analysis by a consortium including county health staff and the women's study, the Buck Institute for Age Research, the Northern California Cancer Center, Zero Breast Cancer, university researchers and others.
Widespread interest was spurred after a National Cancer Institute review indicated Marin's 1998-2002 rate of cancer in non-Hispanic white women was 175 cases per 100,000. At the time, the rate was 7 percent higher than the rest of the Bay Area, 9 percent higher than Los Angeles -- and 18 percent higher than the nation's.
Marin's rate has eased a bit in recent years but remains high. The county posted a rate in 2009 of 147 cases per 100,000 women, eclipsing the state's rate of 139.
Contact Nels Johnson via email at email@example.com
©2012 The Marin Independent Journal (Novato, Calif.)
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