Per- and poly-fluoroalkyl substances, better known as PFAS or “forever chemicals,” cause cancer in humans, according to a new, peer-reviewed study.
Forever chemicals are used in everyday household items and are also present in specialized substances, including the foam used by firefighters — who are at a 21 percent greater risk of developing colorectal cancer than the rest of the population.
Researchers at the Yale School of Public Health have now confirmed exposure to forever chemicals causes colorectal cancer cells cultured in Petri dishes to spread to new locations, indicating they likely also cause cancer cells in the body to spread.
Euronews.com reports: As well as remaining in the environment for long periods, PFAS build up in the human body with toxic effects.
“PFAS make up a prevalent class of persistent organic pollutants of increasing public concern worldwide,” said co-first author Jie Zheng, a postdoctoral associate, at the time the research was conducted.
“They have been frequently detected in the environment, such as in drinking water, indoor dust, cleaning products, and coatings.”
Thanks to their water-resistant and anti-stick properties, PFAS are commonly used in household items like cooking utensils and fabrics.
Studies have found that 97 per cent of people in the US have detectable levels of forever chemicals in their blood.
How are PFAS linked to cancer?
Multiple studies have associated PFAS with higher rates of cancers, including kidney, prostate and breast cancer.
Research is ongoing to understand how the substances affect the body, but exposure to the chemicals, especially at high levels, appears to alter biological pathways.
The new research from scientists at Yale now links forever chemicals with cancer spread, too.
This is worrying as, when cancer metastasises, it becomes more difficult to treat.
The study took two kinds of colon cancer cells, an unmutated or ‘wild type’ and a type with a KRAS mutation.
The latter is a type of oncogene, meaning it has the potential to mutate into a cancerous tumour.
Roughly 30 to 50 per cent of colorectal tumours are known to have a mutated KRAS gene.
Other patients are diagnosed with KRAS wild-type colon cancer, meaning there is no KRAS mutation present.
Colorectal tumours with the KRAS mutation are more dangerous because there is a greater risk of cancer metastasis, where cancerous cells spread to other areas of the body and form new tumours.
The Yale researchers experimented with two types of PFAS of 2μM, or micrometres, long and 10μM long.
They used exposure levels similar to those often observed in firefighters, who have higher instances of the substances in their blood via the foam they use which contains PFAS for their flame retardant properties.
Firefighters are also found to have a 21 per cent higher risk of colon cancer than the general population.
During the study, both types of colon cancer cells were exposed to forever chemicals for seven days.
The researchers found that those cells exposed to PFAS at 10μM showed signs of spreading.
“It doesn’t prove it’s metastasis, but they have increased motility, which is a feature of metastasis,” said Dr Caroline Johnson, principal researcher and epidemiologist at Yale.
When exposed to PFAS at 2μM, the cells did not show signs of growth.
The researchers also performed another experiment where colon cancer cells were laid in a flat layer in a petri dish and divided into two sides.
After being exposed to PFAS at 10μM for seven days, the cells began to grow back together, which is another sign of potential metastasis according to the scientists.
The team at Yale intends to continue its research with lower levels of PFAS chemicals to determine whether it has the same result.