Hepatocellular carcinoma (HCC) is the fifth most common cancer and the third leading cause of cancer death worldwide. Despite recent advances in the diagnosis and treatment of HCC, its prognosis remains dismal. Infection with hepatitis B virus (HBV) and hepatitis C virus (HCV) are the major risk factors for HCC. Although both are hepatotropic viral infections, there are important differences between the oncogenic mechanisms of these two viruses. In addition to the oncogenic potential of its viral proteins, HBV, as a DNA virus, can integrate into host DNA and directly transform hepatocytes. In contrast, HCV, an RNA virus, is unable to integrate into the host genome, and viral protein expression has a more critical function in hepatocarcinogenesis. Both HBV and HCV proteins have been implicated in disrupting cellular signal transduction pathways that lead to unchecked cell growth. Most HCC develops in the cirrhotic liver, but the linkage between cirrhosis and HCC is likely multifactorial. In this review, we summarize current knowledge regarding the pathogenetic mechanisms of viral HCC.

Background and aims: A subset of non-ulcer dyspepsia (NUD) disorders can evolve into peptic ulcer disease. This prospective study attempted to determine the independent risk factors for ulcer formation in NUD patients, and compared the natural history of Helicobacter pylori positive and negative NUD subjects. Methods: From May 1997 to April 1999, consecutive NUD patients were enrolled into the study. Endoscopy was performed routinely on enrolment, at the end of the second and 12th months, and whenever there was a dyspepsia attack. Patients were prospectively followed up for two years. Results: Peptic ulcers occurred in 16 of 209 NUD patients during the two year follow up period. Multivariate analysis of 13 host and bacterial factors demonstrated that advanced age (odds ratio 2.90), H pylori infection (odds ratio 3.59), and use of non-steroidal anti-inflammatory drugs (NSAID; odds ratio 4.46) were independently significant in predicting subsequent peptic ulcer development. NUD patients with all three risk factors had a 75% (3/4) risk of developing peptic ulcer but the ulcer incidence in patients without any of the risk parameters was only 1.2% (1/84). The resolution rate of symptoms in the H pylori positive NUD patients was similar to the H pylori negative patients (57.9% v 49.1%; 95% confidence interval (CI) −5 to 22). However, rates for subsequent peptic ulcer and erosion development were significantly higher in H pylori positive patients than in H pylori negative patients (ulcer 12.6% v 3.5%, 95% CI 1-16; erosion 23.2% v 12.3%, 95% CI 1-21). Conclusion: A small but significant proportion of NUD patients develop peptic ulcer after long term follow up. H pylori infection, NSAID use, and advanced age are independent risk factors for subsequent ulcer formation. Follow up endoscopy is strongly indicated for an NUD patient with multiple risk factors for ulcer formation when symptoms recur.