Wednesday, April 30, 2008

Hormone-Negative Rates Drop; Benefits of Vitamin D

The American Association of Cancer Research met earlier this month in San Diego. Several studies dealt with hormone-negative breast cancer. I highlight a couple of them below.

Estrogen-negative cases drop slightly for most women
Cases of estrogen-receptor-negative breast cancer dropped slightly for white and Hispanic women between 2002 and 2004, but rose for African-Americans, according to researchers from the University of Chicago Medical Center.

Estrogen-negative disease disproportionately affects black women, with 40 percent of their tumors likely to be estrogen-negative compared to 20 percent for white or Hispanic women. And while blacks are less likely to get cancer in the first place, they are more likely to be diagnosed with advanced and more lethal forms, such as triple negative (ER-, PR- and HR2-).

Estrogen-receptor-positive breast cancers also dipped, notably among women 50 to 69, with a 13% drop for whites, 11% for Hispanics, 4% for Asian or Pacific Islanders, but no change for African-Americans. This was tied to a reduction in the use of hormone replacement therapy, which affects estrogen-positive cases because they are fueled by hormones.

The reduction in hormone-negative does not have the logical link to HRT and researchers did not explain the drop in those cases. They speculate that black women may have less access to regular mammograms, which accounts for their tumors being at an advanced stage at diagnosis.

Environmental and social factors may also influence cancer, with women in Nigeria having estrogen-receptor positive tumors 70 percent of the time—a 43 percent increase over African-Americans.

Vitamin D Slows Breast Cancer in Rats
A specific form of active vitamin D known as Gemini 0097 substantially reduced the development of both estrogen-negative and estrogen-positive breast cancer in rats. Researchers at Rutgers University injected rats with breast cancers then treated them with Gemini 0097. The vitamin D slowed the growth of ER-positive by 60 percent and ER-negative by 50 percent.

As with all studies in animals, more research needs to be done to determine the effects of Gemini 0097 on human cancers. One benefit so far is that Gemini 0097 is less toxic than other forms of synthetic vitamin D and does not lead to an overload of calcium, the most common side-effect.

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