Breast Cancer & the Environment Research Program
Michigan State University
NIEHS Grant: U01ES026119
Puberty and young adulthood are periods of high susceptibility to environmental and lifestyle factors that increase breast cancer risk. The research team is identifying how a high animal fat diet (HFD) consumed during puberty or young adulthood increases breast cancer risk. Ovarian hormones are implicated in the etiology of breast cancer. Estrogenic endocrine disrupting chemicals (EDCs) may act as agonists or antagonists during mammary gland development and mammary tumorigenesis and should be studied to evaluate their potential in promoting breast cancer.
The researchers are studying the interaction of HFD with a widely used but understudied EDC, oxybenzone (benzophenone-3, BP-3) – a common ingredient in sunscreen and other personal use products with potential estrogenic activity, to affect breast cancer risk. Using a transdisciplinary approach, findings in mice will be translated to humans to identify predictive biomarkers for risk and intervention strategies to reduce that risk. Recently, HFD was shown to increase premenopausal breast cancer risk in normal weight, but not overweight, young women. These findings agree with the research team’s published and preliminary studies identifying both pubertal and adult windows of susceptibility (WOS) to the promotional effects of HFD in obesity-resistant BALB/c mice. Of note, HFD promoted basal-like breast cancer, which predominantly occurs in young women. The pubertal WOS for HFD tumor promotion indicates potential efficacy of early age preventive interventions to reduce adult breast cancer risk.
The research project aims to:
- Determine, under low fat diet (LFD) and HFD, BP-3 dosages in mice corresponding to seasonal human exposure urine levels and then assess BP-3 effects on pubertal mammary gland development and adult morphology, body weight, and reproductive parameters relevant to the action of BP-3 as an EDC;
- Determine BP-3 effects on mammary tumor susceptibility in two mouse breast cancer models (p53-null and TIP30-null transplant BALB/c mice) fed HFD vs. LFD and identify pubertal vs. adult intermediate biomarkers, focusing on inflammatory and proliferative processes associated with tumorigenesis;
- Test interventions against immune cells and growth factor pathways to alter intermediate biomarkers and ultimately reduce mammary tumorigenesis;
- Analyze a human young adult female established cohort for the relationship(s) among intermediate serum biomarkers, HFD, BMI, and BP-3 exposure that may be predictive of increased premenopausal breast cancer risk;
- Interact regularly with a Breast Cancer Advocate Advisory Board to receive input about the research directions, addressing concerns of affected communities. Board members include individuals from advocacy organizations such as the Huntington Breast Cancer Action Coalition and Michigan Breast Cancer Coalition. Research will be translated for education and risk reduction messages, disseminated in collaboration with Kathy Newkirk from the Michigan State University Extension, and message efficacy will be assessed by Kami Silk, Ph.D. and other communication scientists.
These studies are elucidating mechanisms linking HFD and an understudied EDC with proliferative and immune biomarkers of breast cancer risk. Additionally, these studies are identifying strategies for early prevention and intervention to reduce breast cancer, particularly basal-like mammary cancer for which approaches to intervention are limited.