A Groundbreaking Study on Chemical Mixtures and Breast Cancer Risk
Chemicals linked to breast cancer risk come from many sources: our personal care products, cleaning supplies, food packaging, pesticides, the air we breathe, the water we drink, and more. These chemicals, including endocrine disrupting chemicals and mammary gland carcinogens, can alter vital pathways in our bodies. While most research has focused on single chemicals, in reality, we are not exposed to chemicals one at a time. We are exposed to many chemicals at the same time throughout our daily lives.
Chemical mixtures are combinations of two or more chemicals that can interact with each other and their surroundings, leading to unique effects on human health and the environment. It is not known whether exposures to chemical mixtures have a larger effect on breast cancer risk than exposure to single chemicals. Research is needed to determine whether breast cancer risk is higher depending on the type and amount of chemical mixtures an individual is exposed to, and which chemical mixtures are most impactful.
A groundbreaking new study seeks to uncover the links between exposure to chemical mixtures and the risk of breast cancer. The study will also compare exposures between women who live in neighborhoods with high vs. low levels of socioeconomic disadvantage.
This study is led by Dr. Kimberly Badal, assistant professor in the Department of Surgery, University of California San Francisco. The research will build on ongoing work of the collaborative Athena Breast Health Network in California, which has collected breast health information and blood samples from a diverse cohort of women of different races, ethnicities, and neighborhoods since 2012. The study is funded through a $1.3 million grant from California Breast Cancer Research Program.
Zero Breast Cancer at Collaborative for Health & Environment is a community partner for this research and will focus on communicating the study’s findings to the broader community. This blog post is the first in a series that will delve into this study.
Identifying Who is at Risk
Dr. Badal and her team will use 600 blood samples from Athena Breast Health Network participants, consisting of 300 women who have, and 300 women who have not, developed breast cancer. The samples used will have been taken at least a year before breast cancer developed to ensure chemical mixtures were a potential factor in the development of breast cancer.
The team will then use a tool called non-targeted analysis to screen for up to 100,000 different natural and human-made chemicals or substances in the blood. The goal is to identify any differences in the abundance of chemicals in the blood of women with and without breast cancer and understand how these chemicals, when grouped, might affect breast cancer risk.
Additionally, Dr. Badal and her team will examine differences in DNA methylation between these two groups to see if exposure to chemical mixtures impacts how genes are expressed. DNA methylation analysis looks at how tiny chemical tags called methyl groups, which can turn certain genes on or off, are added to our DNA based on our environmental exposures.
Using AI to Identify Chemical Mixtures
Most research studies have focused on exposure to single chemicals because it has been complex to study chemical mixtures. To address this challenge, Dr. Badal’s study will use machine learning to understand which chemical mixtures are most important and compare the results to more traditional statistical methods.
Machine learning is a type of artificial intelligence that allows computers to find patterns in data without having to give instructions consistently. The machine learning process in data analysis has revolutionized the field of medical research as it can sometimes identify patterns that humans are unable to find. It will help with the investigation of the chemical combinations and key components that elevate the risk of breast cancer.
Guiding Cancer Prevention Efforts
The findings of this study have significant potential to be translated into policy and practice. Through outreach to policymakers, the findings can inform regulatory agencies, such as the Environmental Protection Agency (EPA), to reevaluate and potentially strengthen regulations on the use and release of chemical mixtures associated with breast cancer risk.
Also, the study findings will be used to inform the public directly about the risks associated with exposure to chemical mixtures and how to reduce exposure.
Lastly, the study findings may help to more accurately predict who is at risk for what type of breast cancer and be used to inform breast cancer screening and risk reduction recommendations.
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Written by Collaborative for Health & Environment Science Communications Intern Dr. Bridget Martin
