October 21, 2011
Elevated Hormone Levels Add Up To Increased Breast Cancer Risk
Post-menopausal women with high levels of hormones such as estrogen or testosterone are known to have a higher risk of breast cancer. New research published in BioMed Central's open access journal Breast Cancer Research looked at eight different sex and growth hormones and found that the risk of breast cancer increased with the number of elevated hormones - each additional elevated hormone level increased risk by 16%.
Researchers from the Brigham and Women's Hospital and Harvard Medical School used blood samples collected from nurses up to nine years before health information, including their breast cancer status, was recorded. Post-menopausal women who were diagnosed with breast cancer were matched to two controls of a similar age.
Dr Shelley Tworoger, from Brigham and Women's Hospital, commented that, "Elevated estrogens had the biggest effect on risk, especially for ER positive cancer. However, androgens, and prolactin also contribute to increasing risk of breast cancer. These hormones are known to stimulate the growth of breast cancer cells in the lab and, while androgens can be converted to estrogen in the body, these hormones have also been found to stimulate cancer cell growth in the absence of ER. Our results suggest that models used to assess breast cancer risk could be improved by taking into account multiple sex hormone and growth hormone levels."
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