posted on 08/09/2022 06:00
(credit: MIGUEL MEDINA)
Every year, around 800,000 people are diagnosed with liver cancer worldwide. This is also one of the main causes 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, United States, published in JHEP Reports, shows that a synthetic chemical widely found in the environment — perfluorooctane sulfonate (PFOS) — may be directly linked to non-viral hepatocellular carcinoma, the more common type. common form of liver cancer.
This chemical is part of artificial products called per and polyfluoroalkyl substances (PFAS), used in a wide variety of products to guarantee characteristics such as non-stick, waterproofing and stain resistance. Fast food packaging, non-stick pans and waterproof clothing are examples of products that can have these chemicals.
In addition to offering potential health risks, as the American study shows, PFOS decompose slowly and accumulate in the environment and in human tissues, including the liver. Previous research in animals has suggested that these products could increase the risk of liver cancer, but the study released now is the first to confirm the association using human samples, according to the authors.
The new research, based on the analysis of blood samples, reveals that individuals with the highest concentration of the product (the top 10%) were 4.5 times more likely to develop liver cancer than those with the lowest levels. Evaluation of the samples found evidence that PFOS appears to alter the normal process of glucose, bile acid and branched-chain amino acid metabolism.
Flaws 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 outcomes in liver disease, and this is the first human study to show that PFAS are associated with this disease,” emphasizes Jesse Goodrich, PhD, a postdoctoral scholar in the Department of Population. and Public Health Sciences from the Keck School of Medicine.
Veronica Wendy Setiawan, PhD and professor of population sciences and public health at the Keck School, draws attention to the difficulty in conducting this type of analysis. “Part of the reason there have been few human studies is because you need the right samples,” she explains. “When you’re looking at an environmental exposure, you need samples well before a diagnosis, because it takes time for cancer to develop.”
The team analyzed a repository of long-term 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 taken from participants who did not have the tumor.
The researchers found several types of PFOS in the blood samples that were collected before the participant developed the disease. The group’s expectation is that the study will provide important information about the long-term effects of these products on human health, especially in the occurrence 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 research.