Non-viral hepatocellular carcinoma is the most common type of liver cancer and a new study has found a link between exposure to a synthetic chemical found in the environment, perfluorooctane sulfate (PFOS) – included in a class of chemicals man-made chemicals called peruoroalkylated and polyfluorinated substances (PFAS) – and an increased risk of developing this tumor.
These chemical substances are used in a wide variety of industrial products –textiles, construction, domestic cleaning, electronics, food processing, firefighting, the automotive industry…– and consumer products –fish, fruits, eggs and egg products–, and they are also known as eternal chemicals because they break down very slowly and accumulate in the environment and in body tissues, including the liver. Previous research in animals has suggested that PFAS exposure increases the risk of liver cancer, but this is the first study to find an association using human samples.
PFAs were first detected in the blood of people who had been exposed to these chemicals in the workplace in the 1970s, and in the 1990s they were found in the blood of the general population, which has It has generated concern about its possible health risks and has led the European Food Safety Authority (EFSA) to establish safe intake limits, and to the fact that some manufacturers have dispensed with the use of PFOA and PFOS. However, as long-lasting chemicals, PFAs are found in drinking water and many food products.
The study was conducted by researchers at the University of Southern California (USC) Keck School of Medicine and has been published in JHEP Reports. “This builds on existing research but goes a step further,” said Dr. Jesse Goodrich, a postdoctoral fellow in the Department of Population and Public Health Sciences at the Keck School of Medicine. Liver cancer is one of the most serious endpoints of liver disease and this is the first human study to show that PFAs are associated with this disease.”
PFOS produce alterations that can cause fatty liver
The researchers were able to use human samples that had been collected as part of a large epidemiological study — a collaboration between the medical school and the University of Hawaii — called the Multi-Ethnic Cohort Study, which has followed more than 200,000 residents. of Los Angeles and Hawaii to detect the development of cancer and other diseases.
Individuals in the top 10% of PFOS exposure were 4.5 times more likely to develop liver cancer than those with the lowest blood PFOS levels
This repository of human blood and tissue samples allowed these scientists to find 50 participants who went on to develop liver cancer, evaluate blood samples taken before their cancer diagnosis, and compare them with those from 50 participants in the same study who they did not develop cancer.
They found several types of PFA in blood samples taken before the participant developed liver cancer. The results of the analyzes showed that the strongest association was between PFOS and liver cancer, and that individuals in the top 10% of PFOS exposure were 4.5 times more likely to develop liver cancer than those with the lowest levels of PFOS in the blood.
The researchers were also able to determine the possible pathways by which PFOS would disrupt normal liver function. Evaluating the samples, they found evidence that PFOS appears to disrupt the normal process of glucose metabolism, bile acid metabolism, and the metabolism of a type of amino acid called branched-chain amino acids in the liver.
Disruption of normal metabolic processes in the liver can cause more fat to accumulate in the liver, a condition known as non-alcoholic fatty liver disease (NAFLD). In recent years there has been a significant increase in NAFLD cases worldwide and this constitutes a public health problem because patients with this pathology have a higher risk of developing liver cancer.
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