Exposure to synthetic ‘permanent chemicals’ associated with nonviral hepatocellular carcinoma

Exposure to ubiquitous environmental synthetic chemicals is associated with nonviral hepatocellular carcinoma, the most common type of liver cancer, according to researchers at USC’s Keck School of Medicine. , JHEP Report.

This chemical, called perfluorooctane sulfate or PFOS, is one of a class of man-made chemicals called per- and polyfluoroalkyl substances (PFAS). These chemicals are used in a wide range of consumer and industrial products and are sometimes called permanent chemicals because they degrade very slowly and accumulate in the environment and human tissues, including the liver.

Previous studies in animals have suggested that PFAS exposure increases the risk of liver cancer, but this is the first study to confirm the association using human samples.

It builds on existing research, but goes one step further. Liver cancer is one of the most serious endpoints in liver disease, and this is the first human study to show that her PFAS is associated with this disease. ”

Jesse Goodrich, PhD, Postdoctoral Fellow, Department of Population and Public Health, Keck Medical School

Higher exposure, higher risk

The Keck College of Medicine team was able to use human samples collected as part of a larger epidemiological study, a collaboration between the School of Medicine and the University of Hawaii, called the Multi-Ethnic Cohort Study. The project has tracked the development of cancer and other diseases in her more than 200,000 residents of Los Angeles and Hawaii.

This repository of human blood and tissue samples allowed the research team to find 50 participants who eventually developed liver cancer, assess blood samples taken prior to their cancer diagnosis, and evaluate their blood samples in the same study. 50 people who did not develop cancer.

“One of the reasons there are so few studies in humans is the need for adequate samples,” said Veronica Wendy Setiawan, Ph.D., professor of population and public health sciences at Keck College of Medicine. . “When you look at environmental exposures, you need samples from well before diagnosis because cancer takes time to develop,” she said.

Researchers found several types of PFAS in blood samples taken before participants developed liver cancer. This study found the strongest association between PFOS and liver cancer, with subjects in the top 10% of PFOS exposures more likely to develop liver cancer than those with the lowest levels of PFOS in their blood. found to be 4.5 times more likely to

Chemicals disrupt normal liver function

The research team was also able to reveal how PFOS might alter the normal functioning of the liver. Their evaluation of samples found evidence that PFOS appears to alter the normal processes of glucose metabolism, bile acid metabolism, and metabolism of a class of amino acids called branched-chain amino acids in the liver.

When the liver’s normal metabolic processes are disrupted, fat can accumulate in the liver, a condition known as non-alcoholic. fatty liver disease, or NAFLD. In recent years, there has been a dramatic and unexplained increase in NAFLD around the world, and it is of concern because people with NAFLD are at a much higher risk of developing liver cancer. NAFLD is expected to affect her 30% of all adults in the United States by 2030.

Improving knowledge about the health effects of PFAS exposure

Used in a wide range of consumer and industrial products, PFAS were first detected in the blood of people exposed to these chemicals at work in the 1970s. By the 1990s, they were found in the blood of the general population, raising awareness of their potential health risks.

Although some manufacturers have phased out the use of PFOA and PFOS, they are persistent, and PFAS are found in drinking water, many foods, and the blood of over 98% of U.S. adults. I’m here.

Researchers at the Keck School of Medicine, led by Leda Chatzi, MD, PhD, professor of population and public health sciences, have conducted numerous studies on the link between PFAS exposure and liver damage, liver disease, and now liver cancer. I went to They hope to further validate their findings on the association with liver cancer in a larger study later this year.

“Our study provides important insight into the long-term health effects of these chemicals on human health, particularly how they can impair normal liver function. We think,” said Chatzi. “This study fills an important gap in our understanding of the true consequences of exposure to these chemicals.”