It's estimated that about 240 million people worldwide have an HBV infection. Hepatitis B infections are linked to the development of a common type of liver cancer called hepatocellular cancer. Researchers have now learned more about how the hepatitis B virus (HBV) can set the stage for liver cancer, sometimes even two decades before it's diagnosed. The work has shown that HBV can integrate its genetic material into the DNA of liver cells, which drives cancer risk.The findings have been reported in Nature Communications.
In this study, the researchers performed advanced genetic sequencing in 296 hepatocellular tumor samples that were included in the Pan-Cancer Analysis of Whole Genomes database. This analysis revealed that HBV DNA was present in the DNA of 51 of the samples. In 23 of those samples, the viral DNA caused the host cell's genome to change in significant ways, which the researchers suggested played an important role in the growth of cancer.
Computational tools were applied to this data as well to estimate when the viral DNA had integrated into the host liver cell DNA. That showed that the viral integration had happened about five years or more before the onset of cancer in some cases. In one instance, it had happened about 21 years before the patient was diagnosed with cancer.
"HBV is one of only a handful of viruses currently associated with cancer. It's now becoming clear how this virus can cause large-scale genomic damage, and thereby have a big impact on tumor development. This area of study can offer valuable new insight into cancer formation and evolution," said study co-author Peter Van Loo, a group leader at the Crick and MD Anderson.
"Hepatocellular cancer kills 700,000 people each year," noted first study author Eva Álvarez, a graduate student at the University of Santiago de Compostela. "While not all cases are linked to HBV, and while not everyone with the virus will develop cancer, uncovering more about this relationship could potentially help with finding new treatments or ways to monitor people infected with this virus to identify those at risk."