Limiting carcinogen exposure could mitigate liver cancer risk for people with HBV infection

Hepatitis B virus (HBV) infection is known to be associated with the risk of hepatocellular carcinoma (HCC), but how and why they are connected remains unknown. Researchers from Mass General Brigham discovered that HBV does not cause liver inflammation or cancer on its own, but worsens liver inflammation and may make patients more susceptible to early cancer development caused by environmental carcinogens. Limiting carcinogen exposure or reducing inflammation could mitigate this risk. The results are published in Nature Communications. 

Our research sheds light on the intricate interplay between HBV infection and carcinogen exposure to generate immune dysregulation in the liver that leads to cancer development. We propose the potential of combining statin therapy with conventional HBV treatments like entecavir to improve patient outcomes." 

Shawn Demehri, MD, PhD, corresponding author of the Demehri Lab and Krantz Family Center for Cancer Research at Massachusetts General Hospital

Using a mouse model, the researchers found that HBV did not directly cause liver inflammation or cancer. However, when the HBV models were exposed to a carcinogen found in tobacco smoke, fried foods, processed meats, and alcoholic drinks, they developed an extreme liver cancer phenotype. This carcinogen, also known as diethylnitrosamine (DEN), caused an increase in interleukin-33 (IL-33), an inflammatory molecule, which is required for the development of liver cancer. The researchers then treated the models with pitavastatin, a statin drug, to suppress the expression of IL-33. This treatment was effective in reducing the risk of chronic hepatitis and liver cancer. 

The researchers then extended their findings into humans, finding higher levels of IL-33, especially in patients with HBV-associated hepatitis, compared to healthy controls. They then looked at data from more than 200 million patients, finding that the risk of hepatitis and liver cancer were significantly reduced in patients treated with a statin compared with those treated with another cholesterol-lowering drug.