Continuous exposure to man-made “permanent” chemicals used in a variety of household products has been linked to an increased incidence of cancer.
A new study examining the correlation between liver cancer and the presence of these chemicals in humans found that those with the highest levels were 350% more likely to eventually develop the disease.
The term “persistent” chemicals refers to the more than 4,700 available types of perfluoroalkyl and polyfluoroalkyl substances, or PFASs, commonly used in manufacturing industries—substances that break down very slowly and build up over time in soil, drinking water, and water. in the body.
PFAS was first introduced in the 1930s as a revolutionary material used to make non-stick cookware – hello, Teflon – and soon took advantage of its fluid and fire resistance to adapt to all kinds of products and packaging, from building materials to cosmetics. properties, as outlined by the Centers for Disease Control and Prevention.
Despite their incredible benefits, such chemicals have been linked to cancer and other diseases in laboratory animals. After strong anecdotal evidence that perfluorooctanesulfonic acids (PFOS), along with another common substance called perfluorooctanoic acid (PFOA), were making consumers sick, the Environmental Protection Agency in 2006 ordered eight US multinational manufacturing corporations to stop using the chemicals. . Despite this, as their nickname suggests, PFOS and PFOA are still being found in foreign products, groundwater and humans.
The current study, published in JHEP Reports, is the first to show a clear link between any PFAS and non-viral hepatocellular carcinoma (the most common type of liver cancer) in humans.
“It builds on existing research but takes it a step further,” said Jesse Goodrich, a postdoctoral researcher in public health at the Keck School of Medicine, University of Southern California, in a news release. “Liver cancer is one of the most serious endpoints of liver disease, and this is the first study in humans to show that PFAS is associated with this disease.”
Demonstrating a link between PFAS and cancer in humans has not been easy for scientists.
“One of the reasons there are so few human studies is because you need the right samples,” added Veronica Wendy Setiawan, a professor at the Keck School of Medicine. “When you’re looking at environmental exposure, you need samples taken before diagnosis because cancer takes time to develop.”
To make this leap, the researchers were given access to the Multiethnic Cohort Study, a database of more than 200,000 Hawaii and Los Angeles residents conducted by the University of Hawaii.
Their search was narrowed down to 100 survey participants – 50 of whom had liver cancer and 50 who did not – whose available blood and tissue samples were sufficient for analysis. The researchers looked for traces of “permanent” chemicals in the body before the cancer group became ill.
They reportedly found several types of PFAS in the participants, with PFOS being most prominent in the liver cancer group. Indeed, their study found that those in the top 10% of PFOS exposure were 4.5 times more likely to develop hepatocellular carcinoma than those with the lowest exposure.
A clear link between PFAS and cancer in humans is critical to researching how these chemicals interfere with biological processes. Now, USC scientists have now found that in some subjects, high concentrations of PFOS impair the liver’s ability to metabolize glucose, bile acids and branched-chain amino acids, leading to a healthy accumulation of fat in the body, otherwise known as non-alcoholic fatty liver disease – a high risk for liver cancer.
Therefore, many scientists believe that it is no coincidence that the development and widespread use of “permanent” chemicals is associated with an increase in liver disease, cancer and other diseases.
“We believe our work will provide important insights into the long-term health effects of these chemicals on human health, particularly how they damage normal liver function,” said study author Dr. Leda Chatzi. “This study fills an important gap in understanding the true consequences of exposure to these chemicals.”