According to the World Health Organization, 257 million people worldwide are infected with the hepatitis B virus (HBV). Chronic HBV infection can lead to cirrhosis and hepatocellular carcinoma (HCC), which can have serious complications if left untreated.
With this in mind, researchers at the Center for Gene Diagnosis have created a new HBV assay that can detect closed circular DNA (cccDNA) in serum, single cells and preserved tissue samples. According to the authors, this technique can be used to diagnose HCC at an earlier stage at an earlier stage in order to manage treatment more effectively. Their results were published this week in the Journal of Molecular diagnostics.
The new assay combines droplet digital PCR (ddPCR), known for its sensitivity and accuracy for detecting trace molecules, with PCR. This technique enabled them to detect cccDNA in several sample types with higher sensitivity than the traditional Southern blotting method, which has more difficulty when detecting low copy numbers of cccDNA. Combined analysis of serum cccDNA and HBV-DNA was found to successfully distinguish HCC patients from non-HCC patients in their trials.
"Serum cccDNA is indeed a much better and useful diagnostic marker than intrahepatic cccDNA," said Song-Mei Liu, MD, PhD, of the Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University. Antiviral strategies that target cccDNA have recently emerged as an effective method for HBV clearance, making an accurate and sensitive approach for cccDNA detection of clinical significance for diagnosis and treatment.
Image: Hepatitis B virus (HBV) closed circular DNA (cccDNA) detection is of major clinical significance. HBV entry into the nucleus of liver cells (hepatocytes) stimulates cccDNA to create HBV RNAs that give rise to virus offspring. Measurement of cccDNA levels can help clinicians determine the level of HBV infection. Image courtesy of Song-Mei Liu.