Introduction 

Microplastics—plastic particles smaller than 5mm—have become increasingly prevalent in our environment, found in drinking water, food, air, and even human tissues. As these particles infiltrate our bodies, scientists have begun investigating their potential health impacts, including possible links to breast cancer. 

For more basic information on Microplastics, see the Microplastics section on our Plastics page. 

How Microplastics Impact Breast Cancer Risk 

Scientific studies have identified several pathways through which microplastics can damage cells, including oxidative stress, DNA damage, and changes in gene activity, all known risk factors for cancer development. 

1. Endocrine Disruption

Microplastics often contain or leach chemicals such as bisphenols (like BPA), phthalates, heavy metals, PFAS, and flame retardants—many of which are endocrine-disrupting chemicals (EDCs).  These compounds can interfere with the endocrine system by mimicking natural hormones, interfering with their action, altering hormone synthesis and metabolism, or modifying receptor expression. These changes to the natural working of the body’s own hormone system may increase the risk of breast cancer, particularly when they affect the estrogen hormones involved in breast cancer development. [1]

For breast cancer specifically, chemicals like BPA and other bisphenols can act as estrogen mimics that may fuel hormone-dependent breast cancer in females. This occurs because microplastics can leach these chemicals. Microplastics can also bind and accumulate additional toxic compounds from the surrounding environment, effectively functioning as carriers and a delivery system for harmful substances. [2]

2. Oxidative Stress and Inflammation

Research has shown that ingestion of microplastics can trigger inflammation and irritation, potentially leading to DNA damage that may promote cancer development. Microplastics can intensify inflammatory responses by releasing cytokines (small proteins that help regulate immune response), triggering inflammatory signaling pathways, and inducing oxidative stress—creating a microenvironment conducive to cancer initiation and progression. [3]

A 2023 study demonstrated that polypropylene microplastics (PPMPs) increased the secretion of the pro-inflammatory cytokine IL-6 in breast cancer cells.  IL-6 is known to promote tumor progression, making this a significant finding for understanding how microplastics might worsen existing breast cancer. [4]

3. Direct Cellular Effects

Recent laboratory studies have revealed several direct effects of microplastics on breast cells: 

Research has found significant accumulation of microplastics in tissue samples from breast cancer patients. These microplastics can be engulfed into cells, resulting in mitochondrial damage (mitochondria produce energy for the cell) and initiation of mitophagy (the process of removing damaged mitochondria). [5]

Studies demonstrate that microplastics can alter gene expression in breast cancer cells. For example, polypropylene microplastics were found to accelerate the cell cycle and increase expression of genes associated with tumor progression and metastasis. [6]

Some microplastic particles have been shown to increase cell migration, potentially leading to pro-metastatic effects in cancer cells. This is particularly concerning as metastasis is the primary cause of death in breast cancer patients. [7]

4. Transport of Other Carcinogens

Microplastics can act as vectors for other pollutants through a co-transport mechanism, effectively carrying carcinogens throughout the body. This exposure to cancer-causing compounds through consumption of microplastic-contaminated food may potentially increase breast cancer risk. [8]

What We’re Doing 

BCPP has been at the forefront of addressing the link between plastics and breast cancer risk by translating scientific research and advocating for policies that advance primary prevention. As a science-based advocacy organization founded in 1992, BCPP has focused on eliminating toxic chemical exposures linked to breast cancer, with plastics being a significant area of focus. 

Scientific Education and Awareness 

BCPP has extensively documented how plastics can harm health at every stage of their lifecycle – from petrochemical extraction to production, transportation, use, and disposal – highlighting that plastics are both an environmental justice issue and a source of toxic pollution. BCPP works to translate complex scientific information into accessible education for the public about the health risks associated with plastics. 

Policy Advocacy and Legislation 

BCPP has spearheaded several successful legislative campaigns related to plastic toxicity: 

In 2022, through a coalition effort, BCPP helped convince the FDA to start the process of reconsidering the safety of using bisphenol A (BPA) in polycarbonate plastics, metal can coatings, and other food-contact materials.  

In 2024, we led the winning campaign to pass the California Toxic-Free Medical Devices Act (AB 2300), which bans the toxic phthalate chemical DEHP from plastic IV bags and tubing. This was a significant victory as DEHP is a known endocrine disruptor that can increase breast cancer risk. The bill also prohibited replacing DEHP with other phthalates – thereby avoiding regrettable substitutes. 

In 2025, BCPP advocated for plastics regulation in California by working to ban intentionally added microplastics to personal care and cleaning products. AB 823 passed the legislature but was vetoed by Gov. Gavin Newsom.  

Over several years, we have worked with our coalition partners to pass California bills to eliminate PFAS from paper food packaging, clothing, beauty and personal care products, and firefighting foam.  

In 2025, we co-sponsored California bill SB 682 to phase PFAS out of cookware, cleaning products, dental floss, ski wax, food packaging, and juvenile products, which ultimately passed the legislature but was also vetoed by Gov. Gavin Newsom.  

In 2026, we continue to work on federal and California legislation that would ban bisphenols and phthalates from food packaging (take action on the California bill here).  

We also advocated for a strong Global Plastics Treaty, urging the U.S. government to push for an agreement that will protect health, reduce breast cancer risk, and help save the planet. We also continue to support strong federal legislation that develops safer alternatives in this area, for example the Research for Environmental Uses and Sustainable Economies (REUSE) Act of 2025.  

Partnerships and Accountability 

BCPP works to eliminate toxic chemicals in products, get toxics out of food packaging, remove toxic substances from plastic medical devices, and address “the worst toxics” from plastics.  

We partner with like-minded companies committed to protecting health and the environment, using these relationships to promote safer alternatives to toxic plastic products. Through these partnerships, BCPP creates corporate accountability and works with industry leaders to ensure safer products for consumers. Learn more about our work here. 

Community Engagement and Education 

BCPP provides science-based tools and resources for reducing breast cancer risk, including guidance on avoiding plastic-related exposures. Our educational materials help consumers make informed choices about plastic use in their daily lives. 

BCPP works with allies across the women’s health, environmental health and justice, labor, and consumer right-to-know movements to translate science into useful educational information, push businesses toward safer products, and pass health-protective laws. See the coalition partners named on our project and bill webpages. 

Key Take Aways 

• Microplastics present a potential risk factor for breast cancer through multiple mechanisms, including endocrine disruption, inflammation, oxidative stress, and direct cellular damage. 

• Research indicates that polypropylene microplastics can promote metastatic features in human breast cancer cells, even at concentrations that don’t cause direct cell death.  

• Microplastics can disrupt hormonal action through their ability to leach and transport endocrine-disrupting chemicals, which may be particularly relevant for hormone-dependent cancers like breast cancer. [9] 

• Evidence suggests microplastics can accumulate in breast tissue and affect cellular processes like mitochondrial function. [5]

• While causation has not been definitively established, the increasing breast cancer incidence in the US, Europe and around the world may partially reflect the growing exposure to environmental factors and endocrine-disrupting chemicals found in microplastics. [10]

• More research is urgently needed to fully understand the long-term health impacts of chronic microplastic exposure and to develop effective strategies for reducing exposure and mitigating health risks. 

• On an individual level, reducing plastic use and choosing plastic-free alternatives represents one of the most direct ways to limit exposure to microplastics and their associated chemicals. Read more about how to limit exposure here. 

As research in this field continues to evolve, public health policies and personal choices that reduce plastic pollution from manufacture, use, and disposal, and reduce microplastic exposure may become increasingly important for breast cancer prevention strategies. 

Citations: 

[1] Campanale, Carlo, Carmine Massarelli, Ilaria Savino, Vito Locaputo, and Vito Felice Uricchio. 2020. “A Detailed Review Study on Potential Effects of Microplastics and Additives of Concern on Human Health.” International Journal of Environmental Research and Public Health 17, no. 4: 1212. https://doi.org/10.3390/ijerph17041212. 

[2] Flaws, Jodi, Pauliina Damdimopoulou, Heather B. Patisaul, Andrea Gore, Lori Raetzman, and Laura N. Vandenberg. 2020. “Plastics, EDCs and Health.” Washington, DC: Endocrine Society. 

[3] Chen, Yunjie, Zihang Zhang, Kangming Ji, Qiuchen Zhang, Lijun Qian, and Chuang Yang. 2025. “Role of Microplastics in the Tumor Microenvironment (Review).” Oncology Letters 29, no. 4: 193. 

[4] Park, Jun Hyung, Seungwoo Hong, Ok-Hyeon Kim, Chul-Hong Kim, Jinho Kim, Jung-Woong Kim, Sungguan Hong, and Hyun Jung Lee. 2023. “Polypropylene Microplastics Promote Metastatic Features in Human Breast Cancer.” Scientific Reports 13, no. 1: 6252. 

[5] Tian, Ziying, Boni Ding, Yilin Guo, Jieyu Zhou, Su Jiang, Jiaxue Lu, Nan Li, Xiao Zhou, and Wenling Zhang. 2025. “Microplastics Accumulated in Breast Cancer Patients Lead to Mitophagy via ANXA2-Mediated Endocytosis and IL-17 Signaling Pathway.” Environmental Pollution 364: 125321. 

[6] Dzierżyński, Eliasz, Piotr J. Gawlik, Damian Puźniak, Wojciech Flieger, Katarzyna Jóźwik, Grzegorz Teresiński, Alicja Forma, Paulina Wdowiak, Jacek Baj, and Jolanta Flieger. 2024. “Microplastics in the Human Body: Exposure, Detection, and Risk of Carcinogenesis: A State-of-the-Art Review.” Cancers 16, no. 21: 3703. 

[7] Brynzak-Schreiber, Ekaterina, Elisabeth Schögl, Carolin Bapp, Klaudia Cseh, Verena Kopatz, Michael A. Jakupec, Andreas Weber, et al. 2024. “Microplastics Role in Cell Migration and Distribution during Cancer Cell Division.” Chemosphere 353: 141463. 

[8] Cortés-Arriagada, Diego, Daniela E. Ortega, and Sebastián Miranda-Rojas. 2023. “Mechanistic Insights into the Adsorption of Endocrine Disruptors onto Polystyrene Microplastics in Water.” Environmental Pollution 319: 121017. 

[9] Ullah, Sana, Shahid Ahmad, Xinle Guo, Saleem Ullah, Sana Ullah, Ghulam Nabi, and Kunyuan Wanghe. 2023. “A Review of the Endocrine Disrupting Effects of Micro and Nano Plastic and Their Associated Chemicals in Mammals.” Frontiers in Endocrinology 13 (January 16): 1084236. https://doi.org/10.3389/fendo.2022.1084236. 

[10] Teitelbaum, Susan L., Fiorella Belpoggi, and Les Reinlib. 2015. “Advancing Research on Endocrine Disrupting Chemicals in Breast Cancer: Expert Panel Recommendations.” Reproductive Toxicology 54 (July): 141–47. https://doi.org/10.1016/j.reprotox.2014.12.015.