Plastic Linked to Breast Cancer? UNAM Reveals Shocking Findings

MEXICO CITY (apro) – Researchers at the National Autonomous University of Mexico (UNAM) have found that certain plastic components are a risk factor that could contribute to the development and progression of breast cancer.

Breast cancer ranks among the top oncological diseases in terms of incidence and mortality worldwide. It is estimated that one in every eight women will develop it at some point in their lives.

Moreover, plastic pollution is currently a significant global environmental and public health crisis. Due to the spread of microplastics, an individual might ingest an amount of plastic equivalent to a credit card each week, according to the University of Newcastle, Australia.

Dr. Mariana Segovia Mendoza, a professor and researcher in the Department of Pharmacology at the Faculty of Medicine of UNAM, states that plastics release chemicals that are harmful to health.

The most concerning compounds include bisphenols (such as BPA and its analog bisphenol S BPS) and phthalates, which act as endocrine disruptors, interfering with the normal functioning of the human hormonal system. In recent years, these substances have drawn increasing interest from researchers studying their role in breast cancer.

Three years ago, Segovia Mendoza conducted a study using serum samples from patients with breast cancer, survivors, and healthy individuals collected at hospitals in Mexico City and Toluca. The levels of phthalates and bisphenols were analyzed using mass chromatography.

The findings revealed that cancer patients, especially those with more aggressive types, had significantly higher levels of these pollutants. Survivors showed lower levels, possibly due to the effects of hormonal treatments.

While BPA and BPS do not always accelerate the growth of cancer cells, they can activate metastasis.

Before this study, five years ago, Segovia Mendoza conducted research on two types of breast cancer cell lines:

• MCF7 (luminal, estrogen receptor positive)
• Triple negative (without hormonal receptors)

When she exposed MCF7 cells to BPA and BPS, she noticed they grew more, almost as if they were exposed to natural estrogen. “BPA activated receptors within the nucleus; BPS, those on the membrane,” Segovia Mendoza explained.

In triple-negative cells, there wasn’t much growth, but some receptors were activated, which is significant because it was previously believed that these cells did not respond to such substances.

One of the most altered proteins was VEGF (Vascular Endothelial Growth Factor), which is associated with the formation of new blood vessels and metastasis.

In 2025, Chinese researchers documented the presence of bisphenol A and other endocrine disruptors directly in breast tissue.

These substances stimulate fat formation and abnormal cell proliferation. Excess fat can cause inflammation, and this, along with hormonal changes, creates a conducive environment for cancer development.

Although there are regulations in some parts of the world that limit the use of BPA, its analogs such as BPS and BPF are still used and pose similar risks.

Children, who frequently come into contact with plastic toys and bottles, and women, who may be at higher risk of developing breast cancer due to certain chemical components in plastics, are among the most vulnerable populations to exposure.

As these compounds are liposoluble, they accumulate in fatty tissue, including that of the mammary gland, where they can exert significant biological effects.

The presence of microplastics in food, clothing, and agricultural crops, along with minimal regulation on single-use plastics, exacerbates the situation.

“We must avoid heating food in plastic, prefer glass containers, and demand public policies that regulate the production, use, and disposal of plastic materials,” Segovia Mendoza recommended.

The specialist urgently called for adopting more conscious and responsible practices, reducing the consumption of ultra-processed products in plastic packaging, and advocating for regulations that protect public health.