Extract

What is the relationship between hormones and breast cancer?

Estrogen, the main female sex hormone, is produced mostly by the ovaries. It is responsible for a woman’s sexual development, including the growth of breasts and regulation of her menstrual cycle. At menopause (usually age 51) the ovaries stop producing estrogen but some is still produced in smaller amounts from pre-hormones made by the adrenal glands, which are then transformed into estrogen by fat tissue.

Estrogen travels through the blood stream and attaches to estrogen receptors on specific cells in your body. Breast tissue has these types of cells and is one of the main targets for estrogen. Estrogen stimulates the growth of breast cells. For example, pregnant women have higher estrogen levels that cause the breasts to get larger in preparation for breastfeeding. For this reason, if a woman develops cancer cells in her breast, estrogen can stimulate the growth of that cancer.

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