Increased hepatic oxidative DNA damage in patients with nonalcoholic steatohepatitis who develop hepatocellular carcinoma

The rate of onset of hepatocellular carcinoma (HCC) in patients with nonalcoholic steatohepatitis (NASH) has been reported recently to be comparable to that of patients with chronic hepatitis C. However, the precise mechanism contributing to carcinogenesis in the former remains unclear. Although increased oxidative stress is presumed to play a role in carcinogenesis in patients with NASH, this relationship remains to be directly proven. In this study, we investigated the involvement of oxidative DNA damage in hepatocarcinogenesis in patients with NASH. Patients with nonalcoholic fatty liver disease who were treated at our university hospital were eligible for enrolment in the study(n = 49). The study cohort included 30 patients with NASH without HCC (NASH without HCC), six HCC patients with NASH (NASH-HCC), and 13 patients with simple steatosis. Quantitative immunohistochemistry with a KS-400 image analyzing system was used for 8-hydroxy-2'-deoxyguanosine (8-OHdG) detection. The 8-OHdG content in the liver tissue of NASH-HCC patients was significantly different from that in the other patients. The median immunostaining intensity was 8.605 in the NASH-HCC cases, which was significantly higher than that in the cases of NASH without HCC (4.845; P = 0.003). Multivariate analysis using hepatic 8-OHdG content as a factor in addition to age and fasting blood sugar revealed a significant difference in clinicopathological factors between NASH-HCC and NASH without HCC cases. Old age (P = 0.015) and high relative immunostaining intensity for intrahepatic 8-OHdG (P = 0.037) were identified as independent factors. 8-OHdG content in liver tissue may serve a marker of oxidative stress and could be a particularly useful predictor of hepatocarcinogenesis.