Posted on 08/09/2022 06:00
(Image credit: MIGUEL MEDINA)
Around 800,000 people worldwide are diagnosed with liver cancer every year. It is also a leading cause of deaths from malignant tumors, accounting for more than 700,000 deaths annually, according to the Oncoguia Institute. Research from the University of Southern California, USA, published in JHEP Reports shows that a synthetic chemical that is widespread in the environment perfluorooctane sulfonate (PFOS) is directly linked to nonviral hepatocellular carcinoma, the more common type found in May be associated form of liver cancer.
This chemical is part of manmade products called per and polyfluoroalkyl substances (PFAS), which are used in a variety of products to provide properties such as nonstick, waterproofing and stain resistance. Fast food packaging, nonstick pans, and waterproof clothing are examples of products that can contain these chemicals.
As the American study shows, PFOS not only poses potential health risks, but also slowly degrades and accumulates in the environment and in human tissues, including the liver. Previous research in animals suggested these products could increase liver cancer risk, but the study now published is the first to confirm the link using human samples, the authors said.
The new study, based on analysis of blood samples, shows that people with the highest concentration of the product (the top 10%) are 4.5 times more likely to develop liver cancer than those with the lowest concentrations. Analysis of the samples provided evidence that PFOS appears to alter the normal process of glucose, bile acid and branchedchain amino acid metabolism.
Errors in these processes can cause more fat to accumulate in the organ, a condition known as nonalcoholic fatty liver disease, or NAFLD. “Liver cancer is one of the most serious consequences of liver disease, and this is the first human study to show that PFAS are associated with this disease,” said Jesse Goodrich, PhD, a postdoctoral researcher in the Keck School’s Department of Population and Public Health Sciences of Medicine.
long term
Veronica Wendy Setiawan, PhD and Professor of Population Sciences and Public Health at the Keck School, points out the difficulty in conducting this type of analysis. “One reason human studies are scarce is that you need the right samples,” he explains. “When you’re dealing with an environmental exposure, you need samples well before a diagnosis because it takes time for cancer to develop.”
The team analyzed a collection of longterm human blood and tissue samples taken from more than 200,000 residents of Los Angeles and Hawaii and found 50 participants who had the disease. Then they evaluated the blood samples taken before the diagnosis of the disease and compared them with 50 samples from participants who did not have the tumor.
The researchers found several types of PFOS in the blood samples taken before the participant developed the disease. The group expects that the study will provide important information on the longterm effects of these products on human health, particularly in the presence of liver cancer. “This study fills an important gap in our understanding of the true consequences of exposure to these chemicals,” concludes Leda Chatzi, leader of the study.