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    Pregnancy Hormone May Prevent Breast Cancer

    Animal Studies Suggest HCG Could Become Alternative to Tamoxifen
    WebMD Health News

    April 19, 2005 (Anaheim, Calif.) -- A pregnancy hormone shows promise for preventing breast cancer in women, according to Philadelphia researchers.

    In animal studies, human chorionic gonadotropin (HCG) activated tumor suppressor genes, stopped cancer cell growth, and induced other genetic changes that indicate an anticancer effect, says Irma H. Russo, MD, chief of molecular endocrinology at Fox Chase Cancer Center.

    "Our goal is to eventually use this as a breast cancer preventive in women, just like tamoxifen," she tells WebMD. But unlike tamoxifen, "HCG is normally produced by the body and has no toxic effects."

    Tamoxifen, which has been used to prevent breast cancer, Tamoxifen, which has been used to prevent breast cancer, has been associated with an elevated risk of endometrial cancer and blood clots.

    Early Pregnancy Cuts Breast Cancer Risk

    Studies show that a woman who becomes pregnant by age 20 cuts her risk of breast cancerrisk of breast cancer in half.

    "Over the years, the link between having children and breast cancer protection, particularly if you have children when you're young, became very solid," Russo says.

    "What we found is that rats that were given cancer-causing drugs when they're young, virgin, and in puberty develop breast tumors," she says. "But if you give the same drug after pregnancy, the animals do not develop tumors."

    There's a risk period for developing breast cancer during early puberty,risk period for developing breast cancer during early puberty, when the ovaries first start working and the breasts start developing. "We wanted to try to manipulate [the risk period] and eliminate it," Russo says.

    "We knew pregnancy does it," Russo says, "but the question is, can we do it with hormones?"

    In one set of experiments, researchers gave rats that had just reached puberty a cancer-causing drug to induce breast tumors. They then gave the rats either two weeks of HCG supplements or a combination of estrogen and progestin hormones. The researchers compared the results with virginal and pregnant rats.

    The study was presented by Russo and colleagues at the annual meeting of the American Association for Cancer Research.

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