The findings from a new study suggest that infection with hepatitis B virus (HBV) promotes oncogenesis even in the absence of circulating surface antigen.
Known as occult HBV infection, this type of infection occurs when HBV is detectable in liver tissues but not in the blood. Whether occult infection, like standard infection, is associated with hepatocellular carcinoma (HCC) has been unclear.To investigate, Dr. Teresa Pollicino, from the University of Messina in Italy, and colleagues tested for HBV in liver tissue obtained from 107 patients with HCC and 192 patients with chronic liver disease. All of the patients tested negative for hepatitis B surface antigen.The researchers’ findings are reported in the January issue of Gastroenterology.Tissue HBV DNA was detected in 63.5% of HCC patients compared with just 32.8% of control patients (p < 0.0001). Moreover, the link between tissue HBV and cancer held true after accounting for age, sex, and concomitant hepatitis C virus infection.The authors found that patients with occult infection harbored both integrated viral DNA and covalently closed circular HBV genomes. In addition, the presence of free genomes was tied to persistent viral transcription and replication."Our study definitively shows that HBV also maintains its oncogenic role in the case of occult infection," the researchers state. Therefore, surface antigen-negative patients with progressive liver disease should probably be tested for tissue HBV to assess their risk of HCC. In a related editorial, Dr. Jorge A. Marrero and Dr. Anna S. F. Lok, from the University of Michigan in Ann Arbor, comment that "it is premature to advocate testing all hepatitis B surface antigen-negative patients with HCC for occult HBV infection." Further studies are also needed, they add, to determine the role occult infection plays with HCC: innocent bystander, cofactor, or culprit. (Source: Gastroenterology 2004;126:102-110,347-350: Reuters Health: January 22, 2004: Oncolink)