Evidence is mounting that regular exposure to man-made “permanent” chemicals used in various household products is associated with increased cancer rates.
A new study examining the relationship between liver cancer and the presence of these chemicals in humans found that people with the highest exposure levels had a 350 percent higher chance of eventually developing the disease.
The term “permanent” chemicals refers to the more than 4,700 available types of perfluoroalkyl and polyfluoroalkyl substances, or PFAS, widely used in manufacturing—so named because these substances are found in soil, drinking water and in in the body.
PFAS was first introduced in the 1930s as a revolutionary material for making nonstick cookware – hello, Teflon – and was quickly adapted to a variety of products and packaging from building materials to cosmetics – benefiting from its resistance to liquids and Fire resistance as noted by the Centers for Disease Control and Prevention.
While very useful, these chemicals were later linked to the development of cancer and other diseases in laboratory animals. After strong anecdotal evidence that perfluorooctane sulfonate (PFOS) and another common perfluorooctanoic acid (PFOA) substance made consumers sick, the Environmental Protection Agency in 2006 ordered eight multinational manufacturing companies represented Stop using these chemicals. Still, as their nicknames suggest, PFOS and PFOA are still detected in foreign products, groundwater, and humans.
The study, now published in JHEP Reports, is the first to show a clear association between any PFAS and human non-viral hepatocellular carcinoma, the most common type of liver cancer.
“This builds on existing research, but takes it a step further,” Jesse Goodrich, a postdoctoral public health researcher at the Keck School of Medicine, said in a USC news release. “Liver cancer is one of the most serious endpoints of liver disease, and this is the first human study to show that PFAS is associated with this disease.”
It’s not easy for scientists to show an association between PFAS and human cancer.
“Part of the reason there are so few human studies is because you need the right samples,” adds Veronica Wendy Setiawan, a professor at the Keck School of Medicine. “When you look at environmental exposures, you need to take a sample before diagnosis because it takes time for cancer to develop.”
To make this leap, the researchers gained access to a multi-ethnic cohort study database that required a survey of cancer development among more than 200,000 residents of the University of Hawaii and Los Angeles, California, conducted by the University of Hawaii.
Their search was narrowed down to 100 survey participants — 50 with liver cancer and 50 without — who had enough blood and tissue samples available for analysis. Researchers are looking for traces of ‘permanent’ chemicals that were present in cancer patients before they got sick.
They reported that they found several types of PFAS among the participants, with PFOS being the most prominent among those with liver cancer. In fact, their survey showed that those exposed to the top 10 percent of PFOS were 4.5 times more likely to develop hepatocellular carcinoma than those with the least exposure.
A clear link between PFAS and human cancer is critical for further research into how these chemicals interfere with biological processes. Based on the current findings, USC scientists now believe that high levels of PFOS in some subjects impair the liver’s ability to metabolize glucose, bile acids and branched-chain amino acids, leading to an unhealthy accumulation of fat in the organ, also known as non-alcoholic Sexual fat. Fatty liver disease – a high risk factor for liver cancer.
That’s why it’s no coincidence that many scientists agree that the emergence and widespread use of “permanent” chemicals has been linked to an increase in liver disease, cancer, and other diseases.
“We believe our work provides important insights into the long-term health effects of these chemicals on human health, particularly with regard to how they impair normal liver function,” said study author Dr. Leda Chatzi. An important gap in the understanding of the real consequences of exposure to these chemicals.”