Windows of Susceptibility
“Windows of susceptibility” are defined as specific developmental periods during which an individual is particularly susceptible or vulnerable to breast cancer risk associated with environmental exposures. During windows of susceptibility breast cells are rapidly dividing making the mammary gland more susceptible to certain toxins in our environment. The susceptible time periods are: in- utero, neonatal, pre-pubertal, pubertal, pregnancy, lactation and menopause.
Breast Cancer & Environment Research Project. (BCERP) researchers study windows of susceptibility in animal models and through epidemiological studies of humans. . Since animals have a shorter life span, it is easier to observe biological changes during the windows of susceptibility in them than in human beings.
Through the past five years, BCERP research initiatives have covered and are continuing to follow the lifespan, or windows of susceptibility of laboratory animals and human beings. Some examples of this research are:
Michigan State University: Co-Principal Investigators, Sandra Haslam, Ph.D and Richard Schwartz, Community Partner: Evelyn Barrack, Michigan Breast Cancer Coalition: “Pubertal High Fat Diet: Effects on Inflammation, Mammary Development and Cancer”
Icahn School of Medicine at Mount Sinai: Co-PIs: Susan L. Teitelbaum, PhD, and Jia Chen, ScD. CP Reps: Karen Miller, Huntington Breast Cancer Action Coalition, Inc. and Laura Weinberg, Great Neck Breast Cancer Coalition: “Breast Cancer Genomics in Windows of Susceptibility to Endocrine Disruptors”
Public Health Institute & Columbia University: Co-PIs: Barbara A. Cohn, PhD and Mary Beth Terry, CP Rep: Marj Plumb, DrPH, Plumbline Coaching and Consulting PhD PEDIGREE: “Prenatal Environmental Determinants of InterGenerational Risk”
University of Alabama at Birmingham: PI: Coral Lamartiniere, PhD, CP Reps: Beverly Laird and Rebecca Di Piazza Rawson, Susan G Komen for the Cure, North Central Alabama Affiliate “Combinational Environmental Chemicals Altering Susceptibility for Mammary Cancer”
University of California : PI: Zena Werb, PhD, CP Rep: Janice Barlow, RN, Zero Breast Cancer, “Environmental Effect on the Mammary Gland across the Lifespan”
These investigators and others nationally have been pursuing epidemiological, or population studies involving human subjects focusing on gene-environment interactions as well as environmental influences on breast cancer risk during relevant windows of susceptibility over the life span of an organism.
Certain carcinogens and endocrine disrupting chemicals are environmental influences on the mammary gland that have been researched during windows of susceptibility. Exposures to these chemicals have also been associated with the onset of early puberty, which is a breast cancer risk.
Endocrine disruptors are chemicals that alter normal function of the endocrine system. A variety of chemicals have been found to disrupt the endocrine system; some mimic hormones, while others may block hormones. Women are exposed to combinations of potential endocrine disrupting chemicals through personal care products, certain plastics and pesticides, pharmaceuticals, cleaning products, foods and beverages. These exposures occur throughout a woman’s lifespan.
The following endocrine disrupting chemicals had been studied by BCERP researchers during windows of susceptibility:
Bisphenol A (BPA), an estrogen mimicker may be found in plastic-ware, beverage containers, can linings, infant formula cans and lids, thermal cash receipts.
Methylparaben- Commonly used as antimicrobial preservatives in personal care products, cosmetics, pharmaceuticals and in the processing of foods and beverages.
Diethyl Phthalate– Exposures are high because they are so widely used. Diethyl phthalate (DEP) is found most often in personal care products (fragrances, shampoo, cosmetics and nail polish).
Phthalates- which mimic estrogen, not only affect females but also have anti-androgenic effects on males (inhibit development or maintenance of male characteristics). Phthalates are found in certain plastics, shower curtains, cosmetics, plastic wrap, children’s toys and more.
Triclosan- Commonly used antimicrobial found in personal care and household products ranging from toothpaste, deodorant and hand soap to cutting boards and inner soles of shoes. The hormonal activity of triclosan has not been clearly established and results of many investigations are conflicting.