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What We Need to Know About Bisphenol-A (BPA)

Bisphenol A (BPA) is one of the most pervasive chemicals in modern life. More than 2 billion pounds of BPA are produced in the United States each year, and several times that amount is produced globally. BPA is the building block of polycarbonate plastic
and is also used in the manufacture of epoxy resins. Significant levels of BPA have been measured in ambient air, house dust and river and drinking water.

BPA is commonly found in the lacquer lining of metal food cans and in some types of plastic food containers, including some baby bottles, water bottles, microwave ovenware and eating utensils. Because BPA is an unstable polymer and is also lipophilic (fatseeking), it can leach into infant formula and other food products,
especially when heated. Once in food, BPA can move quickly into people –– a particular concern for women of childbearing age and young children. BPA has been found in blood samples from developing fetuses as well as the surrounding amniotic fluid, and it has been measured in placental tissue and in umbilical cord blood at
birth. CDC researchers also found BPA in 95 percent of about 400 urine samples from a broad national sample of adults.

Several studies using both rat and mouse models have demonstrated that even brief exposures to environmentally-relevant doses of BPA during gestation or around the time of birth lead to changes in mammary tissue structure predictive of later development of tumors. Exposure also increased sensitivity to estrogen at puberty.
Recent data demonstrate that early exposure to BPA leads to abnormalities in mammary tissue development that are observable even during gestation. Prenatal exposure of rats to BPA also led to increases in the number of pre-cancerous lesions and in situ tumors (carcinomas), and an increased number of mammary tumors following adulthood exposures to a sub-threshold dose (lower than that needed to induce tumors) of a known carcinogen.

Studies using cultures of human breast cancer cells demonstrate that BPA acts through the same response pathways as natural estrogen (estradiol). BPA can interact weakly with the intracellular estrogen receptor (ER), and it also can alter breast cell responsiveness and induce cell proliferation in vitro and in vivo. It affects cellular
functions through interactions with the membrane estrogen receptor. Along with its many other effects on cell growth and proliferation, BPA has been shown to mimic estradiol in causing direct damage to the DNA of cultured human breast cancer cells.
Resource from The Breast Cancer Fund www.breastcancerfund. org