What is already known on this topic
Liver cancer is the second leading cause of cancer-related mortality worldwide. The main risk factor for liver cancer is cirrhosis, a late stage of damage of the liver caused by several conditions such as liver inflammation and chronic alcoholism. But whether other factors, including the gut microbiota, play a role in liver cancer is unclear.
What this research adds
By analyzing dietary habits and fecal samples from 95 people, including 30 individuals with cirrhosis and liver cancer as well as 38 individuals with cirrhosis but without liver cancer, researchers found that bacterial richness in people with cirrhosis, either with or without liver cancer, was substantially lower than in healthy individuals. These changes in the gut microbiota increased with the progression of cirrhosis and were more prominent in overweight individuals. Consumption of artificial sweeteners and foods rich in sugar was associated with altered levels of Akkermansia muciniphila in people with cirrhosis and liver cancer.
The findings suggest that the development of liver cancer is associated with alterations of the gut microbiota in people with cirrhosis. For this reason, gut microbes could be used for noninvasive diagnosis of the progression from cirrhosis to liver cancer.
Liver cancer is the second leading cause of cancer-related mortality worldwide. Now, researchers have found that the development of this type of cancer can be associated with alterations of the gut microbiota.
The findings, published in mSystems, suggest that gut microbes could be used for noninvasive diagnosis of the progression of liver cancer.
The main risk factor for liver cancer is cirrhosis, a late stage of damage of the liver caused by several conditions such as liver inflammation and chronic alcoholism. Previous studies suggested that gut microbes are associated with liver cancer, but their role remains elusive. “The altered microbiome may be a cause or a consequence of disease or, more likely, an environmental risk factor or disease modulator,” the researchers say.
Yelena Lapidot at Tel Aviv University in Israel and her colleagues analyzed dietary habits and fecal samples from 95 people, including 30 individuals with cirrhosis and liver cancer, 38 individuals with cirrhosis only, and 27 healthy individuals.
Compared to healthy people, individuals with cirrhosis and liver cancer and individuals with cirrhosis only showed alterations in their gut microbiota composition, including decreased bacterial richness.
People with cirrhosis had lower levels of butyrate-producing bacteria, including members of the Ruminococcaceae and Lachnospiraceae families. These individuals also had higher levels of Gammaproteobacteria and Enterobacteria than healthy people.
Individuals with both cirrhosis and liver cancer had lower levels of Lachnospira, Anaerostipes, and Christensenella as well as higher levels of Fusobacteria, Gammaproteobacteria, Veillonella, and Scardovia bacteria.
The team observed differences in the gut microbiota composition between people with cirrhosis only and those with cirrhosis and liver cancer. In particular, the levels of Alphaproteobacteria, Clostridium, and the CF231 genus of Paraprevotella were altered only in cirrhotic individuals who developed liver cancer, independently of the severity of their cirrhosis and their dietary habits.
What’s more, the researchers found that the consumption of artificial sweeteners and foods rich in sugar was associated with altered levels of Akkermansia muciniphila in cirrhotic people with liver cancer.
The findings show that each stage of chronic liver disease, including liver cancer, is characterized by specific alterations of the gut microbiota. “In the future, there will be a need for further studies of large-scale, multiracial, metagenomic cohorts that include a careful evaluation of environmental factors, including dietary habits and their effect on patients with [cirrhosis and liver cancer],” the researchers say.