Author Interviews, Breast Cancer, Endocrinology, OBGYNE / 13.09.2016
In Utero Exposure to Ethinyl Estradiol Linked to Tamoxifen Resistance and Breast Cancer Recurrence
MedicalResearch.com Interview with:
Leena Hilakivi-Clarke, PhD
Professor of Oncology
Georgetown University
Washington, DC 20057
MedicalResearch.com: What is the background for this study?
Response: About 70% of women who develop breast cancer express estrogen receptors in their cancer. These patients are treated with endocrine therapies that target estrogen receptors. Endocrine therapies are effective in half of the patients, but the other half are resistant to the treatment and recur. Prior to the start of endocrine therapy, there is no way to predict who will respond to it and who will have recurrence of breast cancer. Therefore, it is not known which patients might benefit from an additional therapy to prevent recurrence, and what that additional therapy would entail. We wondered if resistance to endocrine therapy (we used tamoxifen) is pre-programmed by maternal exposure to the estrogenic endocrine disrupting chemical ethinyl estradiol (EE2). Previously, we and others have found that EE2 and other estrogenic compounds, when given during pregnancy, increase breast cancer risk in the female offspring in animal studies and among humans. The current study was done using a preclinical animal model that was used 50 years ago to discover that tamoxifen is an effective endocrine therapy for estrogen receptor positive breast cancer patients.
(more…)