PFAS and Cancer: What New Research Reveals
PFAS are found in many everyday products, from nonstick cookware to waterproof clothing. These chemicals can remain in the environment and human body for years. Now, new research has raised concerns about their possible role in cancer development.
A study published November 5, 2026, in the Journal of Clinical Oncology found a link between two PFAS chemicals and a higher risk of an aggressive type of breast cancer.
The findings add to growing concerns about long-term exposure. However, they do not prove that PFAS directly cause breast cancer.
What are PFAS, and where do they come from?
PFAS stands for per- and polyfluoroalkyl substances. These are a large group of human-made chemicals that have been used since the 1940s.
Manufacturers use them because they resist heat, water, oil, and stains. You may find PFAS in some nonstick cookware, waterproof clothing, stain-resistant furniture, food packaging, and firefighting foam.
People can come into contact with PFAS through contaminated drinking water, food, dust, and consumer products. Some PFAS also enter the environment through industrial waste.
Scientists call them “forever chemicals” because many break down very slowly. Some can also build up in the human body over time.
For example, a person may use nonstick cookware for years without realizing that certain chemicals were used in its manufacture. Someone living near a contaminated industrial site may also face exposure through local water.
What the new PFAS study found
Researchers from the National Institutes of Health (NIH) examined blood samples from women in the Sister Study. This long-running research project follows women who have a sister diagnosed with breast cancer.
The researchers measured 17 different PFAS in blood samples collected before cancer diagnosis. Their analysis included 1,609 women who later developed breast cancer and 2,269 participants in a comparison group.
Two chemicals stood out: PFOA and PFOS.
Women with the highest PFOA levels had a 67% higher rate of estrogen receptor-negative breast cancer than women with the lowest levels. For PFOS, the rate was 93% higher.
These figures describe relative differences between the study groups. They do not mean that an individual woman has a 67% or 93% chance of developing cancer.
Estrogen receptor-negative breast cancer does not rely on estrogen to grow. It can be harder to treat with hormone-based medicines and may have poorer outcomes than some other breast cancer types.
Importantly, researchers found no clear link between PFOA or PFOS and breast cancer overall. The association appeared in the estrogen receptor-negative group.
The study also included a review of earlier research. This analysis found further evidence linking PFOA to this breast cancer type. However, the evidence for PFOS was less certain.
How PFAS may contribute to cancer development
Scientists are still studying how PFAS may affect cells and contribute to cancer.
Some research suggests that certain PFAS can interfere with normal cell processes. These chemicals may cause changes in gene activity, increase oxidative stress, or weaken parts of the immune system.
Such changes matter because healthy cells normally control their growth and repair damage. When these processes stop working properly, abnormal cells may survive and multiply.
However, researchers have not established exactly how PFAS might contribute to estrogen receptor-negative breast cancer in humans.
The International Agency for Research on Cancer (IARC) has also assessed two widely studied PFAS chemicals.
It classified PFOA as carcinogenic to humans. This classification is based on evidence from animal studies and biological research, alongside limited human evidence for kidney and testicular cancers.
IARC classified PFOS as possibly carcinogenic to humans. Evidence linking PFOS to cancer in people remains inadequate.
These classifications apply to specific chemicals. They do not mean every PFAS has the same cancer risk.
Can you reduce your exposure to PFAS?
Completely avoiding PFAS can be difficult because these chemicals are widespread. However, some practical steps may help reduce exposure.
- Check drinking water: If local authorities report contamination, follow their advice. Consider a filter certified to reduce PFAS, such as one meeting NSF/ANSI 53 or 58 standards.
- Review cookware: Consider stainless steel or cast-iron pans if you want alternatives to nonstick cookware.
- Check product labels: Look for products labeled PFAS-free, especially when buying waterproof or stain-resistant items.
- Follow local food advisories: Fish and other foods from contaminated areas may contain PFAS. Follow local safety guidance before eating them.
For example, someone whose drinking water comes from a contaminated source may benefit from checking test results and using an appropriate certified filter.
Filters need regular maintenance to work properly. Boiling water does not remove PFAS.
What the findings mean for cancer prevention
The new findings raise important questions about how environmental chemicals may affect breast cancer risk.
However, they do not show that PFAS exposure caused the cancers in the study. Researchers also examined older chemicals, and the health effects of newer replacements remain unclear.
People should not panic or assume that using a nonstick pan will give them cancer. Exposure does not mean someone will develop the disease.
More research is needed to understand which PFAS pose the greatest risks and how exposure affects different populations.
Bottom Line
PFAS are common chemicals that can persist in the environment and the human body. New research links PFOA and PFOS to a higher rate of estrogen receptor-negative breast cancer.
The findings do not prove that these chemicals cause breast cancer. Still, they strengthen the case for reducing avoidable exposure and studying the long-term effects of these substances.
Frequently Asked Questions
- Do all PFAS cause cancer?
No. PFAS include thousands of different chemicals. Scientists have not established the cancer risks of every substance in this group.
- Which PFAS chemicals have been linked to cancer?
PFOA and PFOS have received the most attention. IARC classifies PFOA as carcinogenic to humans and PFOS as possibly carcinogenic.
- Can you remove PFAS from your body?
No proven home treatment removes PFAS from the body. Reducing further exposure is a practical step, while researchers continue studying ways to limit their health effects.
