In a news release the peer-reviewed journal Environmental Health Perspectives reports on a new study linking chronic exposure of estrogen mimicking bisphenol A (BPA) during rat gestation and lactation to the formation of mammary gland tumors in female offspring. The study of interest by Acevedo et al. “Perinatally administered bisphenol A as a mammary gland carcinogen in rats” was published in Environmental Health Perspectives on September 1, 2013. Acevedo and colleagues report findings of a BPA exposure study. Via subcutaneous pump female Sprague-Dawley rats were exposed up to 250 µg/kg BW/day BPA during gestation, or gestation and lactation. The exposure lead to a mean BPA blood level of 1.25 ng/mL. This blood level is comparable to the concentration of 1 ng/mL found in healthy humans in a biomonitoring study (Vandenberg et al. 2010). Initially searching for preneoplastic lesions, the researchers unexpectedly observed six mammary gland tumors in exposed female offspring 90 days after birth, of which five were classified as adenocarcinomas (potentially invasive and metastatic malignant tumors). No tumors were found in control animals, however. In accordance with other epidemiological studies exposures with elevated levels of estrogen are associated with increased risk of breast cancer in women.

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BPA as a Mammary Carcinogen: Early Findings Reported in Rats , Environmental Health Perspectives (published online September 2, 2013)

Acevedo N, et al. (2013) “Perinatally administered bisphenol A as a mammary gland carcinogen in rats.” Environmental Health Perspectives 121(9), 1040–1046.