Posts Tagged ‘estrogen’

Can Combining Two Safe Level Carcinogens Double Your Cancer Risk?

Friday, July 12th, 2013

logo1267406_mdA new study in the online peer reviewed journal The Prostate concluded that low doses of arsenic and estrogen that singularly are considered safe for humans in combination can cause cancer in prostate cells. In fact, the combination was almost twice as likely to cause cancer in prostate cells. The researchers said the majority of cancers are caused by environmental factors and single dose levels have been tested for their influence on cancer but little has been previously done about combined levels as they influence the development of cancer. Both well water in some areas and cigarette smoke contain arsenic so the researchers wondered how the carcinogenic properties might change if paired with another carcinogenic chemical. . Estrogen was focused upon because of its abundance in the environment in such producrs as plastic, as food can liners and bisphenol A (BPA) that release small amounts of chemicals that mimic estrogen in the body. After finding that two chemicals caused a greater impact they wanted to discover how the two chemicals created that greater effect. they found that the chemicals used do not damage DNA but do stop certasin genes from expressing.

In the study human prostate cells were treated weekly for six months with arsenic, estrogen, and a combination of the two. Many of the tests were with levels of the chemicals considered dafe by the Environmental Protection Agency (EPA). They found that when the two chemicals were used together they stopped the MLH1 ene, that is responsible for sending the signal to start the self-destruct dequence when a cell is damaged. Because the self-destruct could not activate, the cell became cancerous after exposure., The said “With the lower dose not killing the cell, it’s causing damages that go under the cell’s rada.” “We found that  when you have two compounds together, lower doses could be more serious problems>”

Can Early Exposure to BPA Increase the Risk of Later Prostate Cancer?

Friday, June 28th, 2013

logo1267406_mdA new research study published at the recent ENDO meeting (Endocrine Society) in San Francisco concluded that early exposure to BPA (bisphenol A) , an additive commonly found in plastic water bottles and soup can liners, causes an increased risk in an animal model of human prostate cancer. The researcher said “This is the first direct evidence that exposure to BPA during development at the level we see in our day to day environment, increases the risk for prostate cancer in human prostate tissue.”

The increased risk to prostate cancer can be traced ro prostate stem and progenitor cells that become sensitized to estrogen early in development through exposure to BPA mimicking estrogen in the body. and this has become common in our present environment. Prostate stem cells are very long lived and pass on the increased estrogen sensitivity to the prostate tissues produced throughout life. The researcher says because prostate cancer is fueled by naturally rising estrogen levels in aging men, the prostate tissue’s increased sensitivity to estrogen makes the development of cancer much more likely. Currently, more than 95% of expectant mothers had BPA their urine according to research.

Using rats the researchers previously showed that exposure to elevated estrogen or BPA during embryonic development increased the rate of prostate cancer later in life and this study advanced knowledge by using an animal model in which human prostate stem cells were implanted into mouse hosts. To mimic BPA exposure during the early prostate development the researchers fed the mice BPA for the first two weeks after the transplant at doses comparable to those seen in pregnant American women. The tissue was then allowed tro mature for a month into a human prostate-like tissue. The mice were then exposed to elevated estrogen levels for two to four months to mimic the normal rising estrogen levels seen in aging men. . A third of the mice with the human prostate tissue fed BPA showed signs of cancer development compared to 12% of those not exposed to BPA. When the stem cells were exposed to BPA before implantation and again during development 45% showed signs of cancer. Thus, the researchers said “we believe the BPA actually reprograms the stem cells to be more sensitive to estrogen throughout life leading to a life-long increased susceptibility to diseases including cancer.”

Another Study Finds Increased Breast Cancer Risk from Hormone Therapy

Friday, August 20th, 2010

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A new study published in Cancer Epidemiology, Biomarkers & Prevention concluded that the risk of breast cancer varies by personal characteristics but this study reinforced that there is an increased risk of breast cancer from hormone use and further studies are needed to address how specific that risk is. Hormone replacement therapy among 2,857 women were analyzed for almost 10 years and it was found that when compared with women who never used hormone therapy, women who used estrogen therapy for more than 15 years had a 19 percent greater risk of developing breast cancer. For those who used a combined program of estrogen and progestin for 15 or more years the risk increased 83 percent. Thus, the breast cancer risk was highest for the combined hormone therapy group.
Results also showed that breast cancer risk was dependent on body mass index (BMI) because those with a BMI under 30 seemed to have an increased risk with combined therapy and it was highest for women with a BMI under 25. On the other hand obese women with a BMI over 30 had no further risk associated with using combined hormone therapy. The risk for these breast tumors were for tumors that were positive for both estrogen and progestin receptors and were weaker for HER2 negative tumors. Further research is need to answer lingering questions for this complex association.

However, in another study published in the September issue of Cancer Prevention Research researchers found that breast cancer risk varies by the type of progestin used in hormone therapy. In the study they compared the effect of 4 progestins on breast cancer in animal models. Progestins used included 1) synthetic progestin medroxporgresterone acetate (MPA), 2) norgesterel (N-EL), 3) norethindrone (N-ONE) and 4) megestrol acetate (MGA). The MPA progestin in Prempro is most often used by women in the United States for Hormone Therapy. The authors concluded “although previous studies using an animal model for breast cancer found the MPA functions as a tumor promoter, this study showed that N-EL and N-ONE……. strongly inhibited tumor development.” Progestins seems to have tumor stage specific effects that determines whether they function as tumor promoters or protectors. Those such as N-EL and N-ONE seem to prevent breast cancer in women without a history of or family history for breast cancer and for post menopausal women who are at increased risk due to combined estrogen/progestin (MPA) hormone therapy.