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Member Research & Reports

Member Research & Reports

UNC: Researchers Link Estrogen Byproducts to Survival in Breast Cancer Patients

Dr. Marilie Gammon, professor of epidemiology in the University of North Carolina Gillings School of Global Public Health, along with Ms. Tengteng Wang, a doctoral candidate in the epidemiology department, have authored a new study that outlines the potential to gauge survival statistics of breast cancer patients by measuring estrogen byproducts.

At the American Association for Cancer Research Annual Meeting in April, Dr. Gammon and Ms. Wang reported the findings from the study, in which they measured levels of estrogen byproducts in urine from a group of women with breast cancer. Relative levels of “good” versus “bad” estrogen byproducts were linked to survival.

Free estrogen in the body is broken down into several byproducts. One of them is 2-hydroxyestrone, known as a “good” byproduct because it interferes with the cancer-linked effects of estrogen. Another, called 16-alpha-hydroxyestrone, is known as a “bad” metabolite because of its pro-cancer effects that lead to abnormal growth and DNA damage.

“A lot of research has been done to link these two metabolites with the probability of developing breast cancer,” said Ms. Wang. “So far, we believe we are the first to look at the association of metabolites in relation to mortality.”

Dr. Gammon and Ms. Wang found that if the level of 2-hydroxyestrone (the “good” byproduct) was more than, or equal to, 1.8 times the level of 16-alpha-hydroxyestrone (the “bad” byproduct) in urine, there was an associated 26 percent reduced risk of death in women with breast cancer.

One of the major surprises from the study, Dr. Gammon added, was that the association continued in different scenarios that took into account other factors, such as lifestyle, diet, medical history, and whether a woman was pre- or-post-menopausal at diagnosis.

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