Originally published September 17 2013
BPA found to function as a malignant breast tissue carcinogen
by Ethan A. Huff, staff writer
(NaturalNews) Widespread claims that exposure to the ubiquitous plastics chemical bisphenol-A (BPA) at common doses is generally harmless have been proven false, thanks to the findings of a new study recently published in the peer-reviewed journal Environmental Health Perspectives. Researchers from Tufts University in Massachusetts found that perinatal exposure to what are generally considered to be human comparable doses of BPA visibly damage mammary gland tissue and increase the risk of breast cancer.
Acting as an obvious carcinogen, BPA at common environmental exposure levels was observed in rats to induce intraductal hyperplasias, or cell overgrowths that are considered to be the precursors of mammary gland carcinomas in both rodents and humans. Additionally, BPA was found to spur the development of ductal carcinomas, one of the most common types of breast cancer, in rats as young as just 50 days old.
To arrive at these appalling conclusions, the team exposed Sprague-Dawley rats to variant levels of BPA ranging from 0 to 250 micrograms per kilogram (ug/kg). The rats themselves ranged in age from gestational day (GD) 9 to birth, and from GD9 to postnatal day (PND) 21. At four times during the larger BPA exposure trial, all the rats were carefully observed for both preneoplastic and neoplastic lesions, and they were also tested at varying intervals for circulating levels of free BPA, which is considered to be the hormonally active form of BPA.
Much to their surprise, the researchers found that BPA is substantially more harmful than previously thought as far as breast cancer risk is concerned. Exposure to BPA at levels that correlate to what humans experience on a regular basis from things like thermal paper receipts and plastic containers was found to trigger the rapid development of malignant cancer tumors. Even at levels as low as 0.25 ug/kg of BPA, tumor development was observed in many of the rats' mammary glands.
"We were measuring response to internal dose and looking for preneoplastic lesions," Ana Soto, a cancer researcher at Tufts and senior author of the new study, is quoted as saying about the intent of the study. "Instead, what we saw were full-blown tumors."
None of the control rats developed cancer tumors, pointing to BPA as a major cause of breast cancer Conversely, not a single rat in the control group, which was protected from BPA exposure, developed any malignant tumors whatsoever. Despite the fact that the control group was smaller compared to the test group, this still suggests that BPA is an active mammary carcinogen that acts quickly to initiate the tumor formation process, even while the individual being exposed to it is still developing in the mother's womb.
"From the point of view of human health research, the most notable aspect of the study is that the blood levels [of BPA] are very comparable to those found in humans, which isn't always the case with animal studies," says epidemiologist Barbara Cohn, director of the Oakland, California,-based cohort study Child Health and Development Studies, which also looks at environmental factors that play a role in breast cancer development. "This finding may be of great public health significance."
As far as the study itself, the fact that preneoplastic lesions were observed in BPA-exposed female rats across all doses suggests that there is truly no safe level of BPA exposure, and that the chemical must be removed entirely from all consumer products. This is further suggested by the fact that, in as short of a time as PND90, some of the BPA-exposed rats across all doses had already developed actual cancerous tumors.
"Our findings suggest that developmental exposure to environmentally relevant levels of BPA during gestation and lactation induces mammary gland neoplasms in the absence of any additional carcinogenic treatment," conclude the researchers. "Thus, BPA may act as a complete mammary gland carcinogen."
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