Early Life Exposure to Bisphenol A and Breast Neoplasia

Excess estrogen exposure in developing individuals increases the risk of developing breast cancer later in life. This excess estrogen can originate from high levels of maternal endogenous estrogens or from exposure to exogenous endocrine disrupting compounds that mimic estrogen actions. One of those ­compounds is the ubiquitous bisphenol A or BPA, a chemical that has been found in over 90% of the American population tested and that mimics the actions of estradiol both in vitro and in vivo. The breast is a target organ for both estradiol and BPA. In this chapter we will discuss the effects of BPA on the developing mammary gland and its long-lasting consequences on the organ’s health, and we will argue that prenatal and early life exposure to endocrine disrupting chemicals contributes to the increased incidence of breast cancer observed during the last decades.