Important in both the estrous and menstrual cycle, Estrogen is the primary female sex hormone. It is a group of compounds that are necessary for the development of the breast.
The incidence of men versus women who develop breast cancer is low at 1 in every 100 which is why Estrogen is suspected to be a cause, if not the leading cause of breast cancer. More than half of diagnosed breast cancer cases have no known causes; this is another reason why people are pointing fingers at estrogen. The chances of developing breast cancer are increased by the levels of estrogen in your body. The higher your levels of estrogen, the higher the risk factor. Given that women are exposed to estrogen throughout their lifetimes does not bode well for the fairer sex.
Estrogen is responsible for a number of functions in your body. Many of the cells, both cancerous and healthy contain estrogen receptors. A receptor is a form of protein which after coming in contact with estrogen stimulates cell growth. When estrogen comes into contact with a cancerous cell, it causes it to divide. These cells then accumulate in the body. Lack of estrogen would cause the cells to stop growing and eventually die.
17-Betaestradiol is known as the strongest form of estrogen. It can be changed into other forms most notably 2-hydroxyestrone, which is a weaker form or 16-alpha-hydroxyestrone, which is stronger.
The concern raised by researchers is that the 16-alpha-hydroxyestrone form might cause normal breast cells to form abnormalities which may eventually become cancerous.
A recent study carried out on post-menopausal women with breast cancer showed that they had a lower amount of 2-hydroxyestrone verses the 16-alpha-hydroxyestrone when compared to post-menopausal women without breast cancer.
Xenoestrogen – The synthetic Estrogen
Another reason why estrogen has been implicated has to do with xenoestrogen. This is a synthetic estrogen. Xenoestrogens can copy the effect of human estrogen as they have similar chemical structures. This allows them to fit into the estrogen receptors. They may cause an increase in cell division therefore contributing to the risk of breast cancer. Xenoestrogens are not easily broken down and therefore can accumulate. They are stored in the body's fat cells.
If you have a biopsy, your doctor will send the tissue sample taken to a lab for testing. If it contains significantly large numbers of estrogen receptive cells, then it is known as estrogen receptor positive. This is a good thing. The higher the number is the higher the likely hood that the cancer will respond to hormone therapy. Also known as anti-estrogen therapy, it is designed to starve the cancerous cells of the estrogen that they need to grow.
Estrogen metabolism is not simple or extensively studied; therefore it may be premature and unfair to blame estrogen for breast cancer. The question still remains; do some women have a genetic error which does not allow them to process estrogen or xenoestrogen? More studies have to be done to find the answer.